Velvety Brussels Sprouts Gratin with Smoky Bacon

Prepare to have your perception of Brussels sprouts transformed forever with this utterly irresistible, creamy Brussels sprouts gratin. Even the most dedicated sprout skeptics will find themselves reaching for seconds of this luscious dish, brimming with crispy bacon, earthy mushrooms, crunchy pecans, and, of course, a generous blanket of bubbling, melted cheese. Each Brussels sprout is gently caramelized, developing a sweet and nutty flavor that beautifully contrasts with the salty, savory bacon and mushrooms. The pecans introduce a delightful textural crunch, while a rich, velvety cheese sauce binds all these magnificent elements into a symphony of flavors and textures. Honestly, what could be more comforting and delicious?

Brussels sprouts are incredibly versatile and can elevate a wide array of dishes, from simple weeknight dinners to elaborate holiday feasts. If you’re looking for other ways to enjoy this often-misunderstood vegetable, don’t miss my popular Roasted Brussels Sprouts with Bacon for a straightforward yet flavorful option. For those seeking something more substantial and unique, you’ll also find Brussels sprouts making a delightful appearance in my savory Italian Sausage Stuffing, proving just how adaptable they are.

Why This Creamy Brussels Sprouts Gratin Is a Must-Try

This recipe isn’t just another side dish; it’s designed to be a showstopper. Here’s why this creamy Brussels sprouts gratin with bacon and cheese will become your new favorite:

• The Ultimate Brussels Sprouts Experience: While I adore all my Brussels sprouts recipes, this gratin truly stands out. It combines the deep, roasted flavor of Brussels sprouts with the irresistible smokiness of bacon and the comforting embrace of melted cheese. This trio creates a flavor profile that’s simply unmatched, converting even the most adamant sprout detractors.
• Luxuriously Creamy and Cheesy: The secret to its incredible richness lies in the heavy cream base, which, as it bakes, transforms into a silky, savory cheese sauce. This creamy texture beautifully coats every sprout, making each bite an indulgence. The blend of Gruyère and Parmesan ensures a complex, nutty, and wonderfully melty finish.
• Perfect for Any Occasion: Elegant enough to grace your holiday table for Thanksgiving or Christmas dinner, this gratin also works beautifully as an elevated side for a simple weeknight meal. Imagine it alongside grilled chicken, a juicy steak, or a roasted pork loin – it effortlessly adds a touch of gourmet flair to any spread without requiring excessive effort.
• Harmonious Blend of Textures: From the tender-crisp Brussels sprouts and succulent mushrooms to the salty crunch of bacon bits and the added nuttiness and bite from pecans, this dish offers an exciting textural journey in every mouthful.

Essential Ingredients for Your Gratin Success

Crafting this incredible Brussels sprouts gratin relies on a selection of fresh, high-quality ingredients that build layers of flavor and texture. Here’s a closer look at what you’ll need and why each component is vital:

• Olive Oil: Used for sautéing, it helps achieve that perfect caramelization on the Brussels sprouts and mushrooms. You’ll use it for both cooking the bacon and the vegetables.
• Bacon: A true game-changer! Bacon infuses the entire dish with a rich, smoky, and salty flavor that pairs exceptionally well with Brussels sprouts. Opt for a good quality, thick-cut bacon for the best results, chopped into small pieces for even distribution and crispiness.
• Shallot: With a milder, sweeter, and more delicate flavor than a regular onion, shallots provide a subtle aromatic base without overpowering the other ingredients. If you can’t find shallots, a small amount of finely diced yellow onion can be substituted, though the flavor will be slightly more pungent.
• Brussels Sprouts: The star of the show! Fresh Brussels sprouts are essential here. Look for firm, bright green sprouts with tightly packed leaves. Their natural bitterness is beautifully mellowed by roasting and balanced by the creamy sauce.
• Mushrooms: Adding an extra layer of umami and a satisfying “meaty” texture, sliced mushrooms (crimini, bella, or white button work equally well) absorb the flavors of the bacon fat and thyme, contributing to the dish’s overall depth.
• Garlic: Minced fresh garlic adds a pungent, aromatic punch that complements the savory flavors of the bacon and mushrooms, deepening the overall taste profile.
• Fresh Thyme: Earthy and aromatic, fresh thyme provides a wonderful herbal note that elevates the gratin. Its woody undertones are a classic pairing with both mushrooms and rich, creamy sauces.
• Heavy Cream: This is the foundation of our luxurious, creamy sauce. Heavy cream provides the richness and body needed to transform the grated cheeses into a smooth, velvety consistency as the gratin bakes.
• Dijon Mustard: Just a tablespoon of Dijon mustard cuts through the richness of the cream and cheese, adding a delightful, subtle tang and a depth of flavor that brightens the entire dish without making it taste like mustard.
• Nutmeg: A pinch of freshly grated nutmeg is the secret ingredient that rounds out the flavors of a creamy, cheesy gratin. It adds a warm, subtle spice that is traditionally used in French gratin dishes and beautifully enhances dairy-based sauces. Freshly grated is highly recommended for maximum aroma and impact.
• Pecans: Chopped pecans offer a fantastic textural contrast and a lovely nutty flavor. They toast slightly in the oven, providing a wonderful crunch that makes the gratin feel even more special, especially for holiday gatherings.
• Cheese Blend (Gruyère & Parmesan): This combination is key for both flavor and texture. Gruyère cheese is known for its excellent melting properties and rich, nutty, and slightly sweet flavor, contributing to the gratin’s incredible creaminess. Parmesan cheese adds a salty, sharp, and intensely savory kick, providing a perfect counterpoint to the milder Gruyère. Freshly grated cheese is always best for optimal melt and flavor.
• Salt and Pepper: Essential for seasoning each component of the dish to taste, ensuring a balanced and flavorful end result.

Kitchen Equipment You’ll Need

To prepare this creamy Brussels sprouts gratin, you’ll need a few standard kitchen tools:

• Large Skillet: A large, heavy-bottomed skillet (cast iron or stainless steel) is ideal for cooking the bacon, Brussels sprouts, and mushrooms.
• 9×13 Inch Baking Dish: A standard ceramic or glass baking dish of this size is perfect for assembling and baking the gratin.
• Mixing Bowls: Several medium and large mixing bowls will be necessary for combining ingredients.
• Slotted Spoon: Useful for removing cooked bacon while leaving the rendered fat behind.
• Whisk: For preparing the creamy sauce.
• Sharp Knife and Cutting Board: For prepping Brussels sprouts, bacon, shallots, and mushrooms.
• Cheese Grater: Essential for freshly grating Gruyère and Parmesan cheese.

How to Make the Perfect Creamy Brussels Sprouts Gratin

Follow these detailed steps to create a show-stopping creamy Brussels sprouts gratin that will impress everyone:

1. Preparation is Key: Begin by preheating your oven to 400°F (200°C). This ensures the oven is at the correct temperature when you’re ready to bake. Lightly spray a 9×13 inch baking dish with nonstick cooking spray. This crucial step prevents the cheesy gratin from sticking and makes cleanup a breeze.
2. Crispy Bacon Perfection: Chop 4 ounces of bacon into small, bite-sized pieces. In a large skillet, heat 1 tablespoon of olive oil over medium heat. Add the chopped bacon and cook, stirring occasionally, until it becomes wonderfully crisp and golden brown. This usually takes about 5-7 minutes. Using a slotted spoon, carefully remove the crispy bacon from the skillet and transfer it to a plate lined with paper towels to drain excess fat. Critically, leave the rendered bacon grease in the skillet – this flavorful fat will be used to cook the vegetables.
3. Caramelized Brussels Sprouts & Shallots: Add the 2 pounds of halved Brussels sprouts and 1 thinly sliced shallot directly to the skillet with the residual bacon grease. Season lightly with salt and pepper. Cook for about 10 minutes, stirring occasionally, until the Brussels sprouts begin to soften and develop a beautiful caramelization on their cut sides. This browning adds depth of flavor. Transfer the cooked Brussels sprouts and shallots to a medium mixing bowl. Be sure to scrape up any delicious browned bits from the bottom of the pan as these add incredible flavor.
4. Sautéed Mushrooms with Aromatics: Add 1 more tablespoon of olive oil to the same skillet. Then, add 8 ounces of sliced mushrooms (crimini, bella, or white button), 1½ teaspoons of minced garlic, and 3 teaspoons of chopped fresh thyme. Cook for 5-6 minutes, stirring frequently, until the mushrooms have softened, released their moisture, and are lightly browned. The garlic and thyme will become fragrant and infuse the mushrooms with their aromas. Add the cooked mushrooms to the bowl containing the Brussels sprouts and shallots.

5. Combine and Distribute: To the bowl containing the Brussels sprouts, shallots, and mushrooms, add the reserved crispy bacon bits, along with 4 ounces of freshly grated Gruyère cheese and 2 ounces of freshly grated Parmesan cheese. Gently stir all the ingredients together until they are well combined. Then, transfer this savory mixture into your prepared 9×13 inch baking dish, spreading it into an even layer.
6. Crafting the Creamy Cheese Sauce: In a separate larger bowl (you can use the bowl previously used for the Brussels sprouts to minimize dirty dishes), whisk together 2½ cups of heavy cream, 1 tablespoon of Dijon mustard, and 1 teaspoon of freshly grated nutmeg. Whisk vigorously until all ingredients are thoroughly combined and the mixture is smooth. Taste the cream mixture and add salt and pepper as desired – remember the cheese and bacon will add salt, so season cautiously. Pour this rich, creamy sauce evenly over the Brussels sprouts mixture in the baking dish. Carefully toss or gently stir the gratin mixture until all the vegetables, bacon, and cheese are thoroughly coated with the luscious sauce.

7. Bake to Golden Perfection: Place your prepared Brussels sprouts gratin in the preheated oven and bake for 20 minutes. At this point, the sauce should be warming through and the cheese beginning to melt. Carefully remove the dish from the oven. Evenly sprinkle 1 cup of chopped pecans over the top of the gratin. Return the dish to the oven and bake for an additional 10 minutes, or until the sauce is bubbly, the cheese is gloriously melted, and the top is golden brown with toasted pecans.
8. Rest and Serve: Once baked, remove your creamy Brussels sprouts gratin from the oven. It’s crucial to let the dish sit and rest for 5-10 minutes before serving. This resting period allows the creamy sauce to set slightly, preventing it from being too runny when scooped. If you’re feeling extra indulgent, a final sprinkle of freshly grated Parmesan cheese over the warm gratin right before serving is always a welcome touch!

Expert Tips for Gratin Success

Achieving the perfect creamy Brussels sprouts gratin is easier with a few insider tips:

• Prepping Brussels Sprouts Like a Pro: Preparing Brussels sprouts can seem daunting, but it’s simple. First, remove any yellowed, bruised, or loose outer leaves. Then, trim off the tough stem ends. Finally, cut each sprout in half through the stem. You can save time by doing this a day or two in advance and storing the prepped sprouts in an airtight container in the refrigerator until you’re ready to cook.
• The Magic of Fresh Nutmeg: While dried, ground nutmeg can be used, freshly grated nutmeg offers a far superior aroma and flavor, truly rounding out the creamy sauce. If using dried nutmeg, reduce the amount to ¼ teaspoon, as dried spices are more concentrated. You don’t want the nutmeg to overwhelm the delicate balance of flavors.
• Make it Meat-Free (Vegetarian Option): For a delicious vegetarian version, simply omit the bacon. To replace the richness and savory depth, consider cooking your Brussels sprouts and mushrooms in 2 tablespoons of salted butter instead of olive oil and bacon grease. You’ll also want to add a pinch of salt to the vegetables, as they will miss the inherent saltiness from the bacon.
• Savvy Cheese Substitutions: Gruyère is a fantastic cheese for gratins due to its excellent melting qualities and complex flavor, but it can sometimes be pricey or hard to find. Excellent substitutes include Swiss cheese (like Emmental), a mild or medium cheddar for a sharper profile, or even mozzarella for ultimate meltiness. The key is to choose a cheese that melts beautifully.
• Calorie-Conscious Adaptation: If you’re looking to reduce the calorie count, you can swap the heavy cream for half-and-half. Be aware that this will result in a slightly less rich and creamy dish, but it will still be incredibly flavorful.
• Nut-Free Alternatives: For those with nut allergies, you can easily skip the pecans. To maintain a textural crunch, sprinkle some panko breadcrumbs over the gratin during the last 10 minutes of baking. Keep a close eye on it, as panko browns much faster than nuts.
• Leftover Magic: Instant Pasta Sauce! Don’t let any leftover creamy Brussels sprouts gratin go to waste! This brilliant idea transforms leftovers into a delicious pasta sauce. Cook your favorite pasta, reserve a cup or two of the starchy pasta water, and then toss the leftover gratin with the hot pasta and a splash of pasta water. The water will help create a saucy consistency, making a quick and satisfying meal.
• Achieving Optimal Caramelization: Don’t rush the sautéing of the Brussels sprouts. Allowing them to get a nice brown sear in the bacon fat is crucial for developing their sweet, nutty flavor and contributes significantly to the overall taste of the gratin.
• Seasoning in Layers: Season each component as you cook it (bacon, sprouts, mushrooms, cream mixture). This layering of seasoning ensures that every part of the dish is flavorful, rather than just relying on a final salt and pepper addition.

Serving Suggestions: What to Pair with Your Gratin

This creamy Brussels sprouts gratin is a versatile side dish that complements a variety of main courses, making it perfect for both casual meals and festive occasions. Consider pairing it with:

• Roasted Meats: It’s an ideal partner for roasted chicken, turkey, ham, or a succulent pork loin.
• Steak or Lamb: The richness of the gratin beautifully balances a perfectly cooked steak or tender lamb chops.
• Simple Fish: For a lighter meal, serve it alongside baked or pan-seared white fish.
• Holiday Feast: Absolutely essential for Thanksgiving, Christmas, or Easter dinners as a comforting and impressive vegetable side.
• Vegetarian Mains: Pair it with a hearty lentil loaf, a robust mushroom Wellington, or a simple grain dish for a complete vegetarian meal.

Variations and Customizations for Your Gratin

Feel free to get creative with this recipe and make it your own! Here are a few ideas to inspire you:

• Herb Swaps: Experiment with different fresh herbs. Rosemary or sage would be wonderful additions, especially during the colder months.
• Add More Vegetables: Incorporate other quick-cooking vegetables like spinach (wilted into the gratin mixture), chopped leeks, or even small broccoli florets.
• Spice it Up: For a touch of heat, add a pinch of red pepper flakes to the gratin mixture or cream sauce.
• Smoky Flavor Boost: A dash of smoked paprika can further enhance the smoky notes of the bacon.
• Different Nut Choices: While pecans are fantastic, toasted walnuts or even hazelnuts could also provide a delicious crunch.
• Crispy Topping: If you love a crispier topping, consider adding a sprinkle of gluten-free panko breadcrumbs along with the pecans, or even in place of them for a nut-free option.

Make Ahead, Storing, and Freezing Your Gratin

Planning ahead can make mealtime much smoother, but some dishes are best enjoyed fresh. Here’s what you need to know about preparing this gratin in advance, storing leftovers, and freezing:

Make Ahead: For optimal flavor and texture, I highly recommend serving this dish on the same day it’s made. However, if you need to free up oven space or save time on a busy day, you can prep almost everything in advance. Cook the bacon, Brussels sprouts, shallots, and mushrooms, then combine them with the grated cheeses in your baking dish. Cover tightly and refrigerate for up to 24 hours. Whisk the cream mixture separately and store it in the fridge. Just before baking, pour the cream mixture over the vegetable and cheese base, then bake as directed. This ensures the vegetables and bacon don’t become soggy.

Storing Leftovers: Any leftover creamy Brussels sprouts au gratin should be stored in an airtight container in the refrigerator. It will keep beautifully for 3-4 days. Reheat gently in the oven or microwave until warmed through, keeping in mind the texture might soften slightly.

Freezing Advice: I do not recommend freezing any part of this dish. Cream- and cheese-based sauces tend to separate and become grainy when frozen and thawed, and the Brussels sprouts can become overly mushy, compromising the overall quality of the gratin.

Frequently Asked Questions (FAQs)

More Irresistible Creamy Side Dishes to Explore

If you loved this creamy gratin, you’re sure to enjoy these other rich and comforting side dishes:

• Creamy Cauliflower Gratin
• Classic Scalloped Potatoes
• Bacon Green Bean Casserole
• Decadent Funeral Potatoes
• Zesty Mexican Street Corn Casserole

Print Recipe

Creamy Brussels Sprouts Gratin with Bacon

Whitney Wright

Indulge in this exceptionally flavorful side dish! It features a luxurious heavy cream base infused with Gruyere and Parmesan cheese, perfectly crispy bacon, and aromatic fresh thyme.

Prep Time:
20 mins

Cook Time:
30 mins

Total Time:
50 mins

Servings:
12 servings

Ingredients

• 2 tablespoons olive oil – divided
• 4 oz sliced bacon – chopped
• 1 shallot – thinly sliced
• 2 lbs Brussels sprouts – stems removed and halved
• 8 oz mushrooms – sliced (crimini, bella, or white are fine)
• 1 ½ teaspoons garlic – minced
• 3 teaspoons fresh thyme – chopped
• 2 ½ cups heavy cream
• 1 tablespoon Dijon mustard
• 1 teaspoon nutmeg – freshly grated
• 1 cup pecans – chopped
• 4 oz Gruyere cheese – freshly grated
• 2 oz Parmesan cheese – freshly grated
• salt and pepper – to taste

Instructions

1. Preheat oven to 400°F (200°C). Spray a 13×9 inch baking pan with nonstick spray.
2. In a large skillet over medium heat, add 1 tablespoon of olive oil. Add the chopped bacon and cook until crisp. Use a slotted spoon to transfer the cooked bacon to a paper towel-lined plate, reserving the bacon grease in the skillet. Add the thinly sliced shallot and halved Brussels sprouts to the skillet. Season with salt and pepper. Cook for about 10 minutes, or until the Brussels sprouts begin to soften and develop a slight caramelization. Transfer the Brussels sprouts and shallots to a medium bowl.
3. Add the remaining 1 tablespoon of olive oil to the skillet. Add the sliced mushrooms, minced garlic, and chopped fresh thyme. Sauté for 5-6 minutes, or until the mushrooms have softened and cooked down, releasing their moisture. Transfer the cooked mushrooms to the bowl with the Brussels sprouts and shallots. Stir in the crispy bacon, grated Gruyere, and grated Parmesan cheese. Gently mix to combine all ingredients, then transfer the entire mixture to your prepared baking dish, spreading it evenly.
4. In a separate large bowl, whisk together the heavy cream, Dijon mustard, and freshly grated nutmeg until well combined. Taste the mixture and adjust seasoning with salt and pepper as needed. Pour this rich, creamy sauce evenly over the Brussels sprouts mixture in the baking dish. Carefully toss or gently stir the Brussels sprouts to ensure they are thoroughly coated with the creamy sauce.
5. Bake the gratin in the preheated oven for 20 minutes. Remove the dish from the oven and evenly sprinkle the chopped pecans over the top. Return the gratin to the oven and bake for an additional 10 minutes, or until the sauce is bubbly and the top is golden brown. Remove from the oven and let it rest for 5-10 minutes before serving.

Notes

Make Ahead: For best results, enjoy this dish the same day it’s prepared. However, to save time or oven space, you can prepare all ingredients (cook bacon, sprouts, mushrooms, combine with cheese and bacon in the baking dish) except the cream mixture. Store the prepared dish in the fridge. Whisk the cream mixture and pour it over the ingredients just before baking.

Storing Leftovers: Any leftover Brussels sprouts au gratin can be stored in an airtight container in the refrigerator for 3-4 days.

Freezing Advice: We do not recommend freezing this dish, as the creamy sauce may separate and the vegetables can become mushy upon thawing and reheating.

Nutrition

(Approximate values per 1 of 12 servings)

• Calories: 402 kcal (20% Daily Value)
• Carbohydrates: 11g (4% Daily Value)
• Protein: 13g (26% Daily Value)
• Fat: 36g (55% Daily Value)
• Saturated Fat: 17g (85% Daily Value)
• Polyunsaturated Fat: 4g
• Monounsaturated Fat: 13g
• Trans Fat: 0.01g
• Cholesterol: 79mg (26% Daily Value)
• Sodium: 329mg (14% Daily Value)
• Potassium: 483mg (14% Daily Value)
• Fiber: 4g (16% Daily Value)
• Sugar: 4g (4% Daily Value)
• Vitamin A: 1487IU (30% Daily Value)
• Vitamin C: 66mg (80% Daily Value)
• Calcium: 283mg (28% Daily Value)
• Iron: 2mg (11% Daily Value)

*Nutrition information is an estimate and may vary based on specific ingredients and preparation methods.

Course:
Side Dish

Cuisine:
Belgian, French, American

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Recipe adapted from Bon Appétit.