Dinner

Brussels Sprouts Gratin Recipe

ByHarry Bern December 3, 2025December 3, 2025

Introduction

This Brussels Sprouts Gratin is a creamy, cheesy side dish that brings out the best in this often underrated vegetable. With a rich cheese sauce and a lightly browned top, it’s perfect for holiday dinners or a comforting weeknight meal.

The image shows a white oval baking dish filled with golden-brown roasted Brussels sprouts covered with melted cheese. The sprouts are cut in halves with browned edges, and creamy melted cheese coats the top unevenly, creating a mix of green, light brown, and creamy white colors. Some crispy charred bits are visible between the Brussels sprouts and cheese layers. The dish sits on a dark wooden surface with a red and white striped cloth next to it, all placed on a white marbled texture background. Photo taken with an iphone --ar 4:5 --v 7

Ingredients

16 oz Brussels sprouts (trimmed of outer leaves and sliced in half)
1/4 tsp kosher salt
Black pepper (to taste)
Olive oil spray
1/2 tbsp butter
1/3 cup chopped shallots
2 tsp all purpose flour (or gluten free flour for GF)
3/4 cup fat free milk
1/4 tsp kosher salt
1 tsp fresh thyme
1 tbsp grated parmesan cheese
2 oz grated Gruyere cheese (divided)

Instructions

Step 1: Preheat the oven to 400°F. Spray an 8″x12″ gratin dish or casserole with olive oil. Add the Brussels sprouts and season with salt and pepper. Spray some more olive oil over the sprouts. Place the dish in the lower third of the oven and bake for 15 minutes. Toss the sprouts, then bake an additional 10 minutes.
Step 2: While the sprouts bake, heat a medium nonstick pan over medium heat. Add the butter and let it melt. Add the chopped shallots and cook until softened, about 4 to 5 minutes. Sprinkle the flour over the shallots to form a roux, whisking continuously for 1 to 2 minutes.
Step 3: Gradually add the milk while stirring with a wooden spoon until the roux fully incorporates into the milk. Cook the sauce over medium-low heat for about 4 minutes, stirring frequently, until it thickens. Stir in fresh thyme, parmesan, and half of the grated Gruyere until the cheese melts and the sauce is smooth.
Step 4: Pour the cheese sauce evenly over the baked Brussels sprouts. Sprinkle the remaining Gruyere cheese on top. Return the dish to the oven and bake for 15 minutes, until the top is lightly browned and bubbly.

Tips & Variations

For extra crunch, sprinkle panko breadcrumbs mixed with a little melted butter on top before the final bake.
Swap Gruyere for sharp cheddar or fontina for a different cheese flavor.
Use whole milk or cream instead of fat free milk for a richer sauce.

Storage

Store any leftover gratin in an airtight container in the refrigerator for up to 3 days. Reheat gently in the oven at 350°F until warmed through to maintain the crispy cheese topping. Avoid microwaving to keep the texture crisp.

How to Serve

A white oval baking dish filled with cooked Brussels sprouts that have a slightly browned outer layer, covered generously with a creamy white sauce. On top of the sauce, there is a layer of light yellow shredded cheese spread unevenly, adding texture and color contrast. The Brussels sprouts vary in size and are nestled closely together, with some showing open leaves and caramelized edges. The dish sits on a white marbled surface, next to a striped cloth with red, white, and orange colors. photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I prepare Brussels sprouts ahead of time?

Yes, you can trim and halve the Brussels sprouts a day ahead and store them in the fridge. The gratin sauce can also be prepared in advance and combined just before baking.