Name: Cheesy Brussels Sprouts au Gratin Recipe
Prep time: 15 min
Cook time: 35 min
Total time: 50 min
Cuisine: American
Ingredients: 1 pound Brussels sprouts, trimmed and halved; 1 leek, thinly sliced (light green and white parts only); 4 cloves garlic, minced; 1 tablespoon olive oil; 2 tablespoons butter; 1 cup heavy cream; 4 ounces shredded Gruyere cheese; 2 tablespoons flour; 1 teaspoon Dijon mustard; 1/2 teaspoon dried thyme; 1/2 teaspoon rubbed sage; Kosher salt, to taste; Fresh cracked pepper, to taste

Jump to Recipe· 3.8 from 28 reviews

If you’re anything like me, finding ways to make Brussels sprouts irresistibly delicious can be a bit of a quest. Enter the Cheesy Brussels Sprouts au Gratin Recipe—a heavenly, creamy, and cheesy twist on a humble vegetable that will absolutely win over even the pickiest eaters. This dish perfectly balances the natural earthiness of roasted Brussels sprouts with a luscious Gruyere cheese sauce, enlivened by a subtle mix of herbs and a touch of Dijon mustard. It’s comfort food at its finest, a guaranteed crowd-pleaser for any occasion.

Ingredients You’ll Need

The image shows a white marbled surface holding several small white bowls and one silver bowl, each filled with different ingredients. From top left to bottom right, there is light yellow minced garlic in a small white bowl, a white bowl filled with thin, circular slices of pale yellow and white leeks, a silver bowl full of bright green Brussels sprouts cut in halves, a white bowl with shredded pale yellow Gruyere cheese, a small glass jug of cream, a white bowl with white flour, a white plate divided into two sections holding brown-green dried herbs and a small amount of pale yellow Dijon mustard, and a small white bowl with a solid pale yellow piece of butter. Photo taken with an iphone --ar 4:5 --v 7

The beauty of this Cheesy Brussels Sprouts au Gratin Recipe lies in its simplicity. Each ingredient plays a starring role, adding layers of flavor, richness, and texture to the final dish.

Brussels sprouts, 1 pound: Fresh and trimmed, these provide the hearty, slightly nutty base that pairs perfectly with creamy sauce.
Olive oil, 1 tablespoon: Helps roast the sprouts to a tender, slightly crispy perfection.
Butter, 2 tablespoons: Adds smooth richness to the cheese sauce, enriching every bite.
Leek, 1 (light green and white parts): Offers a mild onion-like sweetness that complements the garlic and herbs beautifully.
Garlic, 4 cloves minced: Gives a fragrant depth without overpowering the dish.
Flour, 2 tablespoons: The thickening agent that creates the perfect velvety cheese sauce.
Heavy cream, 1 cup: Brings a luxurious creaminess and smooth texture to the sauce.
Dijon mustard, 1 teaspoon: Adds a hint of tangy sharpness to brighten the cheese sauce.
Dried thyme, 1/2 teaspoon: Infuses a subtle herbal aroma that complements the earthy Brussels sprouts.
Rubbed sage, 1/2 teaspoon: Introduces warm, woodsy notes that make this dish uniquely comforting.
Gruyere cheese, 4 ounces shredded: The star cheese—melts beautifully with a nutty flavor that enriches every creamy bite.
Kosher salt and fresh cracked pepper: Essential seasonings that enhance all the flavors exactly where they need to be.

How to Make Cheesy Brussels Sprouts au Gratin Recipe

Step 1: Roast the Brussels Sprouts

First, heat your oven to 400 degrees. Toss the halved Brussels sprouts with olive oil, salt, and pepper right in your baking dish, giving them a good, even coating. Roasting at this high temperature for about 15 minutes brings out their sweetness and gives them a lovely caramelized edge that makes every bite satisfying.

Step 2: Sauté the Leeks and Garlic

While the sprouts roast, melt butter in a large sauté pan over medium heat. Add your thinly sliced leeks along with a couple pinches of salt and pepper, cooking for 3 to 4 minutes until the leeks soften and release their sweet aroma. Then, toss in the minced garlic and stir for another minute, careful not to let it burn—this layer builds fantastic savory flavor in the sauce.

Step 3: Make the Cheese Sauce Base

Sprinkle in the flour and cook it for about a minute, stirring constantly to avoid lumps. This step is crucial for thickening the sauce. Next, gradually add the heavy cream, stirring steadily, followed by the dried thyme, rubbed sage, Dijon mustard, and more salt and pepper to taste. Let this mixture warm and thicken slightly over gentle heat for a couple minutes—it’s a deliciously aromatic base that signals the cheesy goodness to come.

Step 4: Add the Cheese and Combine

Stir in half of the shredded Gruyere cheese until it’s completely melted and the sauce becomes silky smooth. Pour this lovely sauce over your roasted Brussels sprouts in the baking dish, gently tossing or stirring to coat every sprout with cheesy goodness. Sprinkle the remaining cheese on top to create a bubbly, golden crust once baked.

Step 5: Bake to Perfection

Pop the whole dish back in the 400-degree oven and bake for 15 to 20 minutes. The cheese will bubble and meld beautifully while the sprouts become tender and flavorful. For an extra special finishing touch, you can broil the gratin for 1 to 2 minutes at the end to achieve a gorgeous golden crust—just watch it closely to avoid burning!

How to Serve Cheesy Brussels Sprouts au Gratin Recipe

An oval white ceramic baking dish with blue handles sits on a white marbled surface. Inside, there is a creamy white sauce base with small green broccoli florets spread evenly throughout. On top of the broccoli and sauce is a layer of pale yellow shredded cheese scattered across the surface in thin strips, with some bits overlapping the broccoli. The overall look is fresh and creamy with distinct patches of green broccoli under the cheese. Photo taken with an iphone --ar 4:5 --v 7

Garnishes

A sprinkle of fresh chopped parsley or a dash of smoked paprika can add a lovely pop of color and a hint of freshness to your Cheesy Brussels Sprouts au Gratin Recipe. A little sprinkle of toasted pine nuts or crispy bacon bits also gives an irresistible crunch and depth of flavor.

Side Dishes

This dish pairs beautifully with a wide range of mains. Think roasted chicken, seared steak, or even a simple baked salmon. The creamy richness can also balance well with tangy, crisp salads for a lighter meal option.

Creative Ways to Present

For a fancy gathering, try serving the gratin in individual ramekins for a personalized experience. Another fun idea is layering it in a clear glass casserole dish so your guests can admire the gooey cheese and caramelized edges before diving in.

Make Ahead and Storage

Storing Leftovers

Your delicious Cheesy Brussels Sprouts au Gratin Recipe keeps well in an airtight container in the refrigerator for up to 3 days. The flavors meld even more, so it’s a fantastic make-ahead option for busy weeknights.

Freezing

You can freeze the gratin before baking by covering it tightly with plastic wrap and aluminum foil. Freeze for up to 2 months, then thaw overnight in the refrigerator before baking as usual. Keep in mind that the texture might be a little softer after freezing.

Reheating

Reheat leftovers in a 350-degree oven for about 15 minutes, or until warm and bubbling. This method keeps the Brussels sprouts from getting mushy, and it revives the cheese’s luscious texture beautifully.

FAQs

Can I use frozen Brussels sprouts for this recipe?

While fresh Brussels sprouts give the best texture and flavor, you can use frozen sprouts if you’re in a pinch. Just thaw and pat them dry well before roasting to avoid excess moisture and sogginess.

Is Gruyere cheese essential or can I substitute it?

Gruyere is recommended for its nutty, creamy melting qualities, but you can substitute with Emmental, Swiss, or even a sharp white cheddar to keep the cheesy goodness alive.

Can I make this recipe dairy-free?

This recipe relies on butter, cream, and cheese for its signature richness, but you might experiment with plant-based butter, cashew cream, and dairy-free cheese alternatives. The flavor and texture will differ, but it can still be delicious!

What if I don’t have a leek?

If you can’t find leeks, a mild yellow onion or shallot makes a good substitute, bringing a similar sweetness and depth of flavor to the sauce.

How do I get the cheese sauce thick just right?

Cooking the flour for at least a minute before adding cream prevents a floury taste, and simmering the mixture for a couple minutes helps the sauce reach that perfect creamy thickness. Stir often to avoid lumps!

Final Thoughts

This Cheesy Brussels Sprouts au Gratin Recipe is truly a labor of love that transforms simple ingredients into an unforgettable comfort dish. Whether you’re a Brussels sprout fan or a skeptic, this creamy, cheesy gratin will win your heart and your tastebuds. Don’t hesitate to make it for your next meal—you might just find your new favorite way to enjoy this classic vegetable!