Servings: 12 servings
- 6 tablespoons (3/4 stick) unsalted butter, divided
- 1 1/2 lbs Brussels sprouts, trimmed and halved
- 8 ounces button or cremini mushrooms, sliced
- 1 medium onion, chopped
- Salt and pepper
- 2 cloves garlic, minced
- 2 tablespoons all-purpose flour
- 1 cup chicken or vegetable stock
- 1 cup half and half
- 1 cup panko breadcrumbs
- 1 6-ounce can French fried onions
Step 1Preheat oven to 375°F. Butter a 9x13-inch casserole dish. Set aside.
Step 2Melt 2 tablespoons butter in large skillet set over medium heat. Add Brussels sprouts and cook until browned, about 5 minutes. Transfer to separate bowl and set aside.
Step 3Add mushrooms and onions to skillet, season with salt and pepper, and cook until soft, about 5-6 minutes. Add garlic and cook for 1 minute more. Add to bowl with Brussels sprouts.
Step 4Melt 2 tablespoons butter in medium skillet. Add flour and whisk to form thick paste. Add chicken or vegetable stock gradually while whisking constantly. Whisk in half and half. Increase heat to medium high and bring to boil, whisking frequently. Simmer for about 5 minutes until thickened. Season with salt and pepper to taste.
Step 5Combine Brussels sprouts mixture with sauce and pour into prepared casserole dish. Melt remaining 2 tablespoons of butter and combine with breadcrumbs in medium bowl. Add French fried onions. Scatter mixture on top of Brussels sprouts mixture and bake casserole until bubbly and topping is brown, about 20-25 minutes.
Note: This casserole can be prepared ahead of time. Cover unbaked casserole with plastic wrap and chill in the fridge for up to 1 day. Remove plastic wrap and bake, increasing time to 35-40 minutes.