Brussels Sprouts Casserole (Easy Holiday Side Dish!)
Think you don’t like Brussels sprouts? 🧀😋This Brussels Sprouts Casserole will make a believer out of you! Brussels sprouts are roasted to perfection and smothered with cheese and a creamy sauce that’ll have everyone asking for seconds! An easy side dish that’s great for holiday meals like Thanksgiving, Christmas, or family dinners.
Easy Brussels Sprouts Casserole Recipe
- I adore Brussels sprouts and you don’t have to smother them in cheese or a cream sauce for me to be a super fan, but that doesn’t hurt. If you’re more of a Brussels sprout side dish purist, see my Balsamic Roasted Brussels Sprouts or Orange Glazed Brussels Sprouts.
- But this Brussel sprouts casserole is what holiday dinner table dreams are made of! The earthy, firm texture of Brussels sprouts stands up so well to both gruyere and Parmesan cheese and a creamy sauce.
- Whether it’s for Thanksgiving, Christmas, New Year’s Eve, or fall or winter entertaining, even those who “don’t like Brussels sprouts” will have their minds changed.
- If Brussels sprouts could have a glow up, this is the easy vegetable side dish recipe that’s ready in less than an hour and can make it happen!
Ingredients in Brussel Sprouts Casserole
Brussels sprouts: Since they’re the star of the show, I recommend fresh Brussel sprouts rather than frozen Brussels sprouts, although in a pinch, they’ll suffice. It’s a lot cheaper to buy them loose in your produce department rather than in a sealed bag, not to mention they’ll be fresher. Season them with olive oil, salt, black peppers.
Roux: Unsalted butter and all-purpose flour are cooked together for a minute to form a roux which is what helps the sauce thicken and have body.
Sauce: To the roux, add whole milk or half-and-half (no heavy cream needed), shredded gruyere cheese, shredded Parmesan cheese, garlic and onion powders.
Cheese Substitutions? I know that gruyère is a bit pricier, but the subtle nutty sweet flavor is amazing in this casserole, and it melts like a dream. However, if you need to cut corners, sub with Swiss Cheese or Jarlsberg for more budget-friendly options that still strike a balance between flavor + meltability. I wouldn’t sub anything for the Parm because there’s really nothing like it here.
Note: Scroll down to the recipe card section of the post for the ingredients with amounts included and for more complete directions.
How To Make Brussel Sprout Casserole Recipe
- Roasting Sprouts: Preheat oven to 425F and spray a 7×11 or 2 to 2.5-quart baking dish with cooking spray. Place trimmed and halved (or quartered) Brussels sprouts inside, evenly drizzle with olive oil, salt, pepper, toss to combine, and roast for 20 minutes.
- Make the Roux: While the sprouts roast, to a medium saucepan, add butter, flour, and cook for 1 minute, stirring continuously.
- Make the Sauce: Slowly add the milk while whisking continuously. Add half the gruyere, all the Parm, seasonings, and stir until the cheeses have melted. Ti
- Bake with Sauce: Remove the sprouts from the oven, evenly drizzle the sauce over them, sprinkle with remaining gruyere, (STOP HERE if you want to make it in advance and refrigerate covered for up to 24 hours) and bake for 10-15 mins or until bubbly.
- Optional: Optionally broil for 1-2 minutes to brown the cheese, optionally garnish with crumbled bacon, fresh herbs, more Parmesan, a sprinkle of cheddar, pinch of cayenne, lemon zest, or as desired and serve.
Note: Scroll down to the recipe card section of the post for step-by-step photos and process shots of the cooking process.
- 1 to 1 ¼ pounds fresh Brussels sprouts, trimmed and halved or quartered if they’re extra large (discard any leaves that fall off in the trimming process; frozen is not my recommendation based on texture but theoretically you may use frozen that have been thawed and drained)
- 1 tablespoon olive oil
- 1 teaspoon kosher salt, or to taste
- ½ teaspoon freshly ground black pepper, or to taste
- 2 tablespoons unsalted butter
- 2 tablespoons all-purpose flour
- 1 cup whole milk, or half-and-half
- ½ cup shredded gruyere cheese, divided (I strongly recommend it although Swiss cheese or Jarlsberg may be subsituted)
- ¼ cup grated parmesan cheese, divided
- 1 teaspoon garlic powder
- 1 teaspoon onion powder
- ½ teaspoon salt, or to taste
- ¼ teaspoon freshly ground black pepper, or to taste
- Optional for garnishing: ¾ cup cooked and crumbled bacon, sliced green onions or chives, red pepper flakes, fresh herbs, extra cheese, etc.
- Preheat oven to 425F, and spray a baking dish with cooking spray. Use a 7×11-inch or a 2 to 2.5-quart baking dish, or similar sized.
- Roast Sprouts: Place the trimmed Brussels sprouts in the baking dish, evenly drizzle with olive oil, evenly season with 1 teaspoon salt, 1/2 teaspoon pepper, and use clean hands to toss and coat evenly. Roast for about 20 minutes.
- Roux: While the sprouts are roasting, make the roux. To a medium or large skillet, add the butter, flour, and cook over medium heat for about 1 minute, stirring continuously, to create the roux. This is what helps the sauce thicken later so don’t shortchange this step.
- To the lightly golden browned roux, slowly add the milk, whisking continuously as you add it.
- Creamy Cheese Sauce: Add HALF the gruyere, HALF the Parmesan, garlic powder, onion powder, 1/2 teaspoon salt, 1/4 teaspoon pepper, and stir continuously to melt the cheeses, about 1-2 minutes.
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Remove the Brussels sprouts from the oven, stir and toss them, and evenly pour the cheese sauce over the top. To Make-Ahead, stop now, tightly cover with foil, and refrigerate for up to 24 hours before baking off. If you’re going to do this, make sure to let it sit on your counter for at least 30 minutes to come to room temp before baking because you won’t have good results with a fridge-cold casserole.
- Evenly sprinkle with the remaining gruyere and the remaining Parm.
- Roast with Sauce: Return the baking dish to the oven and bake for about 10-15 minutes, or until the cream sauce and cheese are lightly bubbling, or as golden browned as desired.
- Broil, optionally: If you know how to use your broiler and are confident broiling, you may broil the casserole for 1-2 minutes, or as needed, to lightly brown the top. Tip – Whenever broiling, take care not to become distracted because food can go from underdone to burnt in the span of 30 seconds, and you ruin it all. Keep a very watchful eye on it.
- Garnish, optionally: With bacon, extra cheese, more salt and pepper, etc. as desired, and serve immediately.
Storage: Leftovers will keep airtight in the fridge for up to 4-5 days, taking care to reheat it gently in the microwave for about 30 seconds, or as needed, since there’s a cheesy cream sauce involved. For that reason, I’ve never frozen leftovers, although it may be possible.
Serving: 1serving, Calories: 147cal, Carbohydrates: 10g, Protein: 7g, Fat: 9g, Saturated Fat: 5g, Polyunsaturated Fat: 1g, Monounsaturated Fat: 3g, Trans Fat: 0.1g, Cholesterol: 23mg, Sodium: 580mg, Potassium: 349mg, Fiber: 3g, Sugar: 3g, Vitamin A: 779IU, Vitamin C: 60mg, Calcium: 183mg, Iron: 1mg
