Cheesy Brussels Sprouts Gratin Casserole Recipe for Thanksgiving | @bestrecipebox

Brussels Sprouts Gratin Casserole

Course: Main Course, Side Dish
Cuisine: American
Prep Time: 10 minutes
Cook Time: 50 minutes
Total Time: 1 hour
Servings: 6
Calories: 266 kcal
Brussels sprouts sizes vary so much ranging from the size of a large egg to a small coin. Adjust your cooking times based on the size. Select all the same sizes for consistent cooking. If you like it extra cheesy, then just add more cheese!


  • 2 pounds Brussels sprouts , halved
  • 3 Tablespoons butter
  • 2 Tablespoons flour
  • 1-1/4 cups  milk
  • 1 cup  grated parmesan cheese , extra for topping if you like
  • 1/2 teaspoon kosher salt
  • 1/4 cup  mayonnaise
  • 1/2 teaspoon garlic powder
  • black pepper to taste


  1. Pre-heat oven to 375° F.
  2. Clean, trim stems of Brussels sprouts. Cut in half and keep all of loose leaves. Fill medium stock pot half way with water, bring to boil. Add Brussels sprouts, stirring in hot water and blanch quickly for about 2 minutes or until they turn bright green. Immediate drain. Do not cook Brussels sprouts too long and make them soft!
  3. In large pan melt butter, then add flour and quickly stir with whisk to combine and remove clumps. Turn off heat.
  4. Add milk, salt, cheese, mayo, garlic powder and black pepper. Stir until cheese is melted.
  5. Add Brussels sprouts and combine with cheese mixture. Pour into baking dish and bake for about 40-50 minutes or until Brussels sprouts are tender.
  6. If you want an extra cheese crusted, top with grated parmesan cheese before baking.

Recipe Video