Brussels Sprout Casserole

This Brussels sprout casserole makes this vegetable taste like mac and cheese! Bake tender sprouts with a white cheddar cheese sauce and top with crunchy breadcrumbs. It’s a showy side dish everyone in our family loves.

Here’s a rich and delicious side dish that will have everyone talking about it: this Brussels sprout casserole! Because, really—what’s better than making Brussels that taste like mac and cheese?

Bake up those tender sprouts with a rich and creamy white cheddar cheese sauce, then top it with crunchy breadcrumbs toasted until they’re golden brown. It’s truly sublime—and we’re not just saying that! This recipe is our go-to for a cozy homey side dish that wins everyone over. We’ve made it for Thanksgiving a few times and everyone sings it’s praises (then asks us for the recipe!).

Flavor makers in this Brussels sprout casserole

This Brussels sprout casserole has three basic elements that make its magic: sauteed Brussels sprouts with shallots and garlic, a white cheddar cheese sauce, and a crunchy breadcrumb topping. It’s a great side dish for Thanksgiving, Christmas, or any festive fall or winter meal. It also works as a vegetarian main dish, similar to mac and cheese. Here’s what you need:

Brussels sprouts, shallots and garlic make the powerhouse vegetable flavor.
Butter, flour, and milk create a creamy roux to thicken the sauce.
Onion powder and garlic powder add savory seasonings.
White cheddar cheese brings a sharp, savory flavor.
Pecorino Romano cheese is the key: it’s an aged cheese that’s like a saltier version of Parmesan. If desired, you can substitute Parmesan cheese and another pinch of salt. but Pecorino brings a unique flavor.
Panko bread crumbs add a crunchy topping.

How to prepare the Brussels sprouts

For this Brussels sprouts recipe, you’ll to slice the Brussels sprouts into quarters. Here’s why, and a few tips:

Slicing into quarters makes them easier to sauté. The first step is to make sautéed Brussels sprouts, and they cook faster and more evenly in smaller pieces.
Got super large Brussels sprouts? We’ve gotten some massive ones at the store. Cut them in half, then into thirds to make sixths. Very small Brussels can likely just go in half. The goal is to have everything in similar sized pieces.
Remember the weight for the sprouts is off the stem. It’s easiest to buy them in bags from the store: usually you can find one pound bags.

Tips for the white cheddar cheese sauce

This Brussels sprout casserole features a white cheddar cheese sauce that’s made like a traditional mac and cheese sauce using a roux. A roux (pronounced “roo“) is a way to thicken sauces by cooking equal parts flour and butter. Here are a few things to keep in mind when making the sauce:

Measure out your ingredients first (mise en place). The cooking process goes fast, so you don’t want to be distracted by measuring. The French way to say this is mise en place, which “means everything in its place”.
Don’t leave the stove, and watch closely. The flour and butter can burn easily! Stand by the stove and start adding milk right when the flour turns golden brown.
Add the milk gradually. Pour in the milk and constantly whisk, adding it little by little, until it forms a smooth sauce. Then add the cheese and stir until it melts.

Ways to serve Brussels sprouts casserole

There are so many ways to serve this Brussels sprouts casserole: it works as a side dish or a main dish! It’s just like mac and cheese but using Brussels sprouts instead of pasta, so it’s the ideal vegetarian main dish. Use it in the following ways:

As a side with baked chicken, baked fish, or as part of a vegetarian dinner
As part of a Thanksgiving spread or Christmas table
As a vegetarian main dish with a green salad and another easy side dish

Make ahead tips

Want to make this Brussels sprouts casserole for a big meal and make some portions ahead of time? Here’s what to do:

Sauté the Brussels sprouts in advance, then refrigerate until ready to prepare. Re-warm them in the skillet for a few minutes prior to adding the sauce.
Make the cheese sauce in advance, then refrigerate. The sauce will thicken in the refrigerator. Before preparing the casserole, re-warm the sauce with the Brussels sprouts in the skillet.

Dietary notes

This Brussels sprout casserole recipe is vegetarian.