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Easy Cheesy Brussels Sprouts Au Gratin

Brussels Sprouts Au Gratin is a new way you can prepare Brussels sprouts. Fresh Brussels sprouts are baked in a creamy cheese sauce with crispy bacon.

overhead view of Brussels sprouts au gratin with bacon in a baking dish.

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What Makes Brussels Sprouts Au Gratin a Side Dish That Needs To Be On Your Table 

Sure, go ahead and make jokes about brussels sprouts. Turn your nose up at them if you wish, but you’ll miss out on one of the most delicious and versatile side dishes you can make.

If you are not already a fan of this much-maligned vegetable, then this Brussels Sprouts Au Gratin recipe is likely to change your mind. Not only is it deliciously hot and creamy, but it is also pretty nutritious!

What Makes This Recipe So Good?

Everything is better with bacon! Adding bacon to this dish delivers a subtle smoky taste that perfectly complements the earthy flavors in the brussels sprouts.

When combined with the slight nuttiness of a young gruyère cheese and the creaminess of the bechamel sauce, you wind up with a very special au gratin. 

Ingredients For Au Gratin Brussels Sprouts

To prepare this dish, you’ll need:

  • Fresh brussels sprouts
  • Butter
  • All-purpose flour
  • Whole milk
  • Salt
  • Ground black pepper
  • Gruyere cheese
  • Bacon, cooked 

Use a young gruyere in this recipe since less-aged gruyeres have a creamier texture and a slightly nutty flavor profile. Older gruyeres tend to have more earthy notes. 

For the smoothest and creamiest sauce, it is best to grate the cheese yourself using a fine-hole grater. Manufacturers usually use an anti-caking additive to keep their pre-shredded cheeses from clumping. This additive also prevents the cheese from melting easily, which can be problematic in this recipe. 

Brussels sprouts au gratin ingredients.

How To Make This Brussels Sprouts Casserole

To prepare the creamiest, crunchiest brussels sprouts that you have ever had:

  1. Preheat the oven to 350°F.
  2. Rough chop the cooked bacon.
  3. Remove any withered or discolored outer leaves from the brussels sprouts and rinse them well. Pat the brussels sprouts dry with a kitchen towel.
  4. Trim off the tough stem but don’t remove so much that the leaves start to separate.
  5. Cut the brussels sprouts in half longways.
  6. Dump the prepped brussels sprouts into a 9×13 casserole dish and shake them into a single layer. Set aside for later.
  7. Melt the butter in a saucepan over medium heat.
  8. Sprinkle the flour into the pan while whisking well. Continue to whisk and let the butter and flour mixture cook for about a minute until it is a light tan and smells like baked pie dough.
  9. Slowly pour in the milk and stir until the sauce thickens slightly.
  10. Season with salt and fresh pepper.
  11. Stir in the cheese in batches until it melts and the sauce is smooth.
collage of brussels sprouts au gratin cheese sauce recipe steps.
  1. Pour the cheese sauce over the brussels sprouts in the casserole dish.
  2. Sprinkle the bacon on top.
  3. Put the dish in the oven and bake for 45 minutes, rotating the pan halfway through to ensure even cooking.
  4. Remove the casserole from the oven and allow it to cool slightly before serving. 
collage of brussels sprouts au gratin recipe steps.

Brussels Sprouts Au Gratin Recipe Variations

Feel free to customize this recipe depending on your tastes and what ingredients you have available. Here are a few suggestions you may want to try:

  • Replacing gruyere with gouda for an extra boost of smokiness in the dish.
  • Add a couple of tablespoons of parmesan cheese to the sauce.
  • Sauteing a couple of tablespoons of minced shallots in the butter before adding the flour to add a new layer of flavor.
  • Substituting cooked sausage or pancetta for the bacon. 
Brussels sprouts au gratin in a baking dish and a serving on a plate.

What To Serve With Brussels Sprout Casserole 

This is a wonderful side for any roasted meat or poultry dish. Serve it with steak or even as an appetizer with plenty of toasted bread. 

How To Store the Leftovers

Let any extra au gratin brussels sprouts cool to room temperature before storing them in an airtight container for up five days in the refrigerator. While you can freeze leftovers, since this dish contains a dairy-based sauce, it may separate slightly once reheated.

What’s the Best Way to Reheat Brussels Sprout Casserole

To reheat thawed brussels sprouts gratin:

  1. Preheat the oven to 350°F.
  2. Set the Brussels Sprouts Au Gratin on the counter for at least ten minutes to eliminate some of the chill from the fridge.
  3. Cut the casserole into portions and place them in a clean baking dish. 
  4. Cover the baking dish with aluminum foil and bake for about 25 minutes or until the casserole is warmed through. 
Brussels sprouts au gratin serving on a stack of plates.

Love Easy Oven Baked Side Dishes? Check Out These Recipes

More Brussels Sprouts Recipes

Be sure to look at more delicious side dishes recipes and cooking on a budget.

overhead view of Brussels sprouts au gratin with bacon in a baking dish.

Brussels Sprouts Au Gratin

Brussels Sprouts Au Gratin is easy to make and reheats so well.

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Course: Side Dish

Cuisine: American

Keyword: Brussels Sprout Au Gratin

Prep Time: 15 minutes

Cook Time: 45 minutes

Total Time: 1 hour

Servings: 8

Calories: 218kcal


  • 2 pounds Fresh Brussels sprouts
  • 3 tablespoons butter
  • 3 tablespoons all-purpose flour
  • 2 1/2 cups whole milk
  • 1/2 teaspoon salt
  • 1/2 teaspoon ground black pepper
  • 1 cup Gruyere cheese
  • 1/2 cup diced cooked bacon


  • Preheat oven to 350°F. Wash, trim, and cut Brussels sprouts in half. Place Brussels sprouts in a 9×13-inch baking dish.

  • In a medium-size saucepan over medium heat, add 3 tablespoons of butter. When the butter has melted add the flour. Whisk together the butter and flour and continue to cook for about 1 minute. The butter and flour mixture will become fragrant like pie dough. Slowly add in the milk and continue to whisk. The sauce will thicken. When all of the milk has been incorporated into the sauce continue to stir and cook until the sauce thickens. Season with salt and pepper. Slowly add in the cheese and stir to incorporate the cheese into the sauce. Cook until the cheese has fully melted. 

  • Pour cheese sauce over the Brussels sprouts, and then top with the crispy cooked bacon. Bake in the oven for about 45 minutes.


Calories: 218kcal | Carbohydrates: 16g | Protein: 11g | Fat: 13g | Saturated Fat: 7g | Cholesterol: 38mg | Sodium: 311mg | Potassium: 555mg | Fiber: 4g | Sugar: 6g | Vitamin A: 1265IU | Vitamin C: 96.4mg | Calcium: 302mg | Iron: 1.8mg

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