If you’re looking for a cozy, crowd-pleasing side dish that manages to be both comforting and sophisticated, this Cheesy Brussel Sprouts au Gratin Recipe is exactly what you need. Tender roasted Brussel sprouts basked in a velvety, herb-infused cheese sauce create an irresistible combination that will have everyone asking for seconds. Whether you’re serving it alongside a holiday roast or simply want to elevate your weeknight vegetables, this dish strikes the perfect balance between rich, creamy, and fresh flavors that highlight the natural goodness of Brussel sprouts in a way that feels downright luxurious.

Ingredients You’ll Need

The image shows several small white bowls and a glass jug arranged on a white marbled surface. There is one white bowl filled with pale yellow shredded gruyere cheese sitting in the center, a bigger white bowl with thin light green leek rings to the top right, and a medium white bowl containing fresh green halved Brussels sprouts to the bottom right. A small white bowl with white flour is on the left side. Another small white bowl has a pat of light yellow butter, placed near the center. A very small white bowl contains dried green herbs and a dollop of pale yellow Dijon mustard. A small pink bowl holds minced garlic. Finally, a clear glass jug is filled with off-white cream. photo taken with an iphone --ar 4:5 --v 7

These ingredients keep the dish simple yet flavorful, each playing its part to deliver that irresistible cheesy, creamy texture and vibrant taste. Every item is essential for creating those layers of flavor and achieving the perfect golden finish.

1 pound Brussel sprouts: Fresh, trimmed, and halved for perfect roasting and texture.
1 tablespoon olive oil: Helps caramelize the sprouts and adds a delicate fruitiness.
2 tablespoons butter: Creates a luscious base for the creamy sauce.
1 leek, thinly sliced: Adds a subtle sweetness and mild onion flavor that complements the sprouts.
4 cloves garlic, minced: Gives a punch of aromatic depth without overpowering the dish.
2 tablespoons flour: Thickens the sauce to that perfect, indulgent au gratin consistency.
1 cup heavy cream: Brings richness and silkiness to the sauce.
1 teaspoon Dijon mustard: Introduces a gentle tang and complexity.
1/2 teaspoon dried thyme: Offers a warm, woodsy herbal note.
1/2 teaspoon rubbed sage: Compliments thyme with earthy, savory undertones.
4 ounces shredded Gruyere cheese: Melts beautifully to give that signature golden crust and nutty flavor.
Kosher salt: Enhances all the flavors throughout the dish.
Fresh cracked pepper: Provides a mild heat and brightness to balance the richness.

How to Make Cheesy Brussel Sprouts au Gratin Recipe

Step 1: Roast the Brussel Sprouts

Start by heating your oven to 400 degrees. Toss the halved Brussel sprouts with olive oil, salt, and pepper, then spread them out in a baking dish. Roasting for about 15 minutes will bring out their natural sweetness and create a tender texture with just the right amount of caramelization on the edges.

Step 2: Prepare the Flavorful Leek Base

While the sprouts roast, melt butter in a large sauté pan over medium heat. Add thinly sliced leeks along with some salt and pepper. Cook for 3 to 4 minutes, stirring frequently, until the leeks soften and begin to release their gentle sweetness.

Step 3: Build the Garlic and Flour Roux

Into the softened leeks, stir in minced garlic and cook for about a minute until fragrant. Then sprinkle the flour over the mixture, stirring continuously for another minute so it can cook through and serve as the thickening agent for your sauce.

Step 4: Whisk in Cream and Herbs

Slowly add the heavy cream, then stir in Dijon mustard, dried thyme, and rubbed sage. Let this simmer for a couple of minutes, stirring often, until the sauce warms through and begins to thicken slightly, teasing out rich and savory herbal aromas.

Step 5: Melt the Cheese into the Sauce

Stir in half of the shredded Gruyere cheese until fully melted and incorporated. Taste, then season with salt and pepper accordingly to balance the creamy, cheesy mixture perfectly.

Step 6: Combine and Bake

Pour the cheese sauce over the roasted Brussel sprouts, gently tossing them to ensure every bite is coated in that luscious mixture. Top with the remaining Gruyere cheese, then return the dish to the oven and bake for 15 to 20 minutes, or until the sprouts are tender and the top is bubbling and golden brown.

How to Serve Cheesy Brussel Sprouts au Gratin Recipe

This image shows an oval white baking dish with dark blue handles placed on a white marbled surface. Inside the dish, on the bottom layer, there are small green Brussels sprouts scattered evenly. They are covered by a creamy white sauce with visible black pepper flakes mixed throughout. On top of this layer, there is a generous sprinkling of shredded pale yellow cheese spread evenly across the surface. The overall texture looks smooth and creamy with the Brussels sprouts peeking through and the cheese adding a slightly textured top layer. photo taken with an iphone --ar 4:5 --v 7

Garnishes

To add an extra pop of freshness and texture, sprinkle a little chopped fresh parsley or thyme leaves on top just before serving. A light dusting of smoked paprika also adds a beautiful color contrast and a subtle smokiness that works wonders with the cheesy sauce.

Side Dishes

This gratin makes a stellar companion to roast chicken, pork tenderloin, or a juicy steak. It’s equally delicious alongside a simple grain like quinoa or wild rice to soak up the extra cheese sauce, making your meal balanced yet indulgent.

Creative Ways to Present

For special occasions, try serving the Cheesy Brussel Sprouts au Gratin Recipe in individual ramekins or mini cast-iron skillets for a charming, rustic presentation. You can also sprinkle some crunchy toasted breadcrumbs or chopped toasted nuts on top just before baking to add a satisfying crunch.

Make Ahead and Storage

Storing Leftovers

Place leftover gratin in an airtight container and store it in the refrigerator for up to 3 days. The flavors meld beautifully overnight, making it just as tasty—if not more—when reheated.

Freezing

This dish freezes well when cooled completely. Store in a freezer-safe container with a tight lid and freeze for up to 2 months. Thaw overnight in the fridge before reheating.

Reheating

Reheat leftovers in the oven at 350 degrees until warmed through, usually about 15 to 20 minutes. This keeps the cheese sauce creamy and prevents the sprouts from becoming mushy, maintaining that delightful texture.

FAQs

Can I use a different cheese?

Absolutely! Gruyere is classic for its meltability and nutty flavor, but cheddar, fontina, or even a mix with Parmesan can be delicious alternatives. Just choose cheeses that melt well and complement the Brussels sprouts.

Do I have to roast the Brussel sprouts first?

Roasting brings out sweetness and helps give the sprouts a tender-yet-crisp texture that contrasts beautifully with the creamy sauce. Skipping this step may result in a softer, less flavorful dish.

Can I make this dish vegan?

To make a vegan version, substitute the butter with plant-based margarine, use a non-dairy cream alternative, and swap the Gruyere for vegan cheese. Nutritional yeast can also enhance the cheesy flavor.

Is this recipe suitable for large gatherings?

Definitely! The Cheesy Brussel Sprouts au Gratin Recipe scales well. Simply increase the quantities and bake in a larger dish. It’s a fantastic vegetarian option that pleases many palates.

How can I add more texture to this dish?

Try sprinkling toasted breadcrumbs or crushed nuts on top before baking. You can also toss some cooked bacon bits into the sauce for a smoky crunch if you’re not keeping it vegetarian.

Final Thoughts

There’s something truly special about the Cheesy Brussel Sprouts au Gratin Recipe that turns everyday vegetables into a show-stopping dish. With its creamy, cheesy sauce and perfectly roasted sprouts, every bite feels like a cozy celebration. I encourage you to give it a try—you might just find your new favorite way to enjoy Brussel sprouts!