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Brussels Sprouts Casserole

Brussels sprouts casserole with a creamy Gruyère sauce and a crisp panko-bacon crust. Baked until bubbly and golden, with melted cheese strands that stretch when you scoop.
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Prep Time 15 minutes
Cook Time 40 minutes
Total Time 55 minutes
Servings: 8 servings
Course: Side Dish
Cuisine: American
Calories: 520
Ingredients Equipment Method Notes

Ingredients
  

Brussels sprouts
  • 2 lb Brussels sprouts trimmed and halved
Bacon
  • 6 bacon slices, chopped
Aromatics and roux
  • 2 clove garlic minced
  • 2 tbsp butter
  • 2 tbsp all-purpose flour
Creamy base
  • 1.5 cup whole milk
  • 0.5 cup heavy cream
  • 1 cup shredded Gruyere divided (use 1 cup in sauce)
  • 0.5 cup shredded Gruyere divided (use remaining for topping)
  • 0.5 cup grated Parmesan
  • 0.5 tsp salt
  • 0.25 tsp black pepper
Topping
  • 0.5 cup panko breadcrumbs

Equipment

  • 1 sheet pan

Method
 

Preheat and blanch
  1. Preheat the oven to 400F. Blanch the Brussels sprouts in boiling salted water for 4 minutes, then drain thoroughly so they don’t water down the casserole.
Cook bacon and make the sauce
  1. Cook the chopped bacon until crisp, then remove it and reserve 1 tablespoon of drippings. Keep the bacon aside for layering.
  2. Melt the butter with the reserved drippings, add the minced garlic, and cook for 1 minute while it smells fragrant. Whisk in the flour, then cook 1 minute to form a smooth roux.
  3. Whisk in the whole milk and heavy cream, then simmer until thickened, stirring to avoid lumps. Stop when the sauce coats the back of a spoon.
  4. Stir in 1 cup shredded Gruyere, Parmesan, salt, and black pepper until smooth. The mixture should look glossy and fully melted.
Assemble and bake
  1. Fold the drained Brussels sprouts and half the bacon into the cheese sauce, then pour into a baking dish. Spread into an even layer for consistent browning.
  2. Top with the remaining Gruyere, remaining bacon, and panko breadcrumbs. Press lightly so the topping adheres.
  3. Bake for 20-25 minutes at 400F until bubbly and golden. Look for bubbling at the edges and browned panko for a crisp crust cue.

Notes

For the best texture, drain the blanched Brussels sprouts very well before folding into the sauce so the casserole bakes thick instead of watery. Refrigerate leftovers in an airtight container for up to 3 days; reheat in a 350F oven until warmed through (about 15-20 minutes). Freezing is not recommended because the creamy sauce can separate after thawing. For a lighter version, swap half the heavy cream for more whole milk while keeping the cheese amounts the same.