Brussel Sprout Casserole

4.99 from 85 votes

Easy to make, this creamy and cheesy Brussel sprout casserole is a crowd pleasing side dish. Serve up the vegetarian gratin for Thanksgiving!

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This deliciously cheesy Brussel sprout casserole is an excellent side dish to serve with your Thanksgiving or holiday dinner. Easy to make, this vegetarian gratin recipe is always a real crowd pleaser even if you’re not a fan of brussels!

Brussel Sprout Casserole after baking in the oven with cheesy top

How to make the recipe

  1. Cut brussel sprouts and place them in a baking dish and season. Give them a good toss
  2. Roast until golden brown; you can toss half way through if you’d like.
  3. Make the creamy sauce in a saucepan on the stovetop, and pour over the roasted Brussels sprouts.
  4. Sprinkle cheese on top of that creamy sauce and bake one more time until the cheese is bubbly.
4 Image collage to show how to make the recipe

Tips for making brussel sprout au gratin

  1. Remove the outer leaves of the sprouts before roasting them. The outer leaves can be dry and tough, so just peel them off before you cut the sprouts in half.
  2. Ensure that the sprouts are well covered with the oil. Use your hands to toss them so that the sprouts are fully covered and they will crisp up all over. I always use my hands for coating vegetables before roasting…it’s just the best way to coat them!
  3. Make this Brussel sprout casserole gluten-free. Use 1:1 GF flour when making the sauce instead of all-purpose. You can also use almond flour if you’d like.
  4. Opt for smaller sprouts when shopping. The smaller ones have more mild flavor so they don’t have that strong cruciferous taste that the bigger ones have. This is especially helpful for first-time brussel eaters!

Frequently asked questions

Can you make it ahead of time?

If you want to get ahead with things, you can either make the whole dish ahead of time and then reheat it in the oven to serve, or roast the spouts the day before and keep them covered in the fridge and then carry on with the recipe the next day. They may soften though so I prefer them roasted the same day.

Can you freeze it?

Yes! This spout casserole freezes really well. Let the gratin cool completely before wrapping the dish in foil and placing it in a freezer bag. It will keep well for up to 2 months and can be thawed in the fridge overnight before reheating. You can also freeze individual portions in freezer safe containers or sealable bags.

What do you serve it with?

This Brussel sprout casserole is a great vegetarian dish to serve up on Thanksgiving along with your other favorite sides. Try it with:
Roasted Turkey
Oven Baked Stuffed
Rosemary Garlic Smashed Potatoes
Oven Roasted Carrots
Green Beans with Almonds

More recipes with brussel sprouts:

If you’ve tried this healthy-ish feel good Brussel Sprout Casserole recipe or any other recipe on FeelGoodFoodie, then don’t forget to rate the recipe and leave me a comment below! I would love to hear about your experience making it. And if you snapped some shots of it, share it with me on Instagram so I can repost on my stories!

Brussel Sprout Casserole

Easy to make, this creamy and cheesy Brussel sprout casserole is a crowd pleasing side dish. Serve up the vegetarian gratin for Thanksgiving!
5 from 85 votes
Servings 6 servings
Course Side Dish
Calories 143
Prep Time 15 mins
Cook Time 35 mins
Total Time 50 mins


  • 1 pound brussel sprouts trimmed and sliced
  • 1 tablespoon olive oil
  • ½ teaspoon salt
  • ¼ teaspoon black pepper
  • ¼ teaspoon garlic powder
  • 1 tablespoon butter
  • ¼ cup finely chopped onions
  • 2 tablespoons all-purpose flour
  • 1 teaspoon mustard powder
  • 1 cup fat free milk
  • ½ cup grated Gruyere cheese divided


  • Preheat the oven to 425°F.
  • Place brussel sprouts on an 8 x 11 rimmed baking dish, drizzle with olive oil and season with salt, pepper and garlic powder. Toss to coat evenly, and then roast until golden brown, about 20-25 minutes, tossing halfway through.
  • In a small saucepan over medium heat, melt the butter. Add the onions and cook until translucent, about 3-5 minutes. Add the flour and mustard powder and stir until the flour dissolves, about 1-2 minutes. Slowly pour the milk and stir with a wooden spoon until the sauce thickens. Add ¼ cup gruyere cheese and stir until well blended.
  • When the brussel sprouts are done roasting, pour the sauce over the brussel sprouts. Sprinkle remaining gruyere cheese on top.
  • Return the brussel sprouts to the oven and cook until the cheese is melted and bubbly, about 15 more minutes. Serve warm.


Storage: Store any leftovers in an airtight container. They will last up to 3 days in the fridge.
Substitutes: For best results, follow the recipe as is. However here are some common substitutes that would work well in this recipe.
  • Instead of regular milk, you can use any unsweetened plant-based milk.
  • Instead of gruyere cheese, you can use shredded cheddar cheese or another one you like.
  • To make this gluten-free, use an all-purpose gluten-free flour mix. You can also substitute with almond flour.


Calories: 143kcal, Carbohydrates: 12g, Protein: 8g, Fat: 8g, Saturated Fat: 4g, Cholesterol: 18mg, Sodium: 284mg, Potassium: 376mg, Fiber: 3g, Sugar: 4g, Vitamin A: 816IU, Vitamin C: 65mg, Calcium: 193mg, Iron: 1mg

Nutrition information provided is an estimate. It will vary based on cooking method and specific ingredients used.

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Brussel Sprout Casserole after baking in the oven with cheesy top

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  1. The sauce was extremely thick . I recommend using half the amount of flour. Other than that I will
    Definitely make it again

    1. Definitely do! You can also reduce the time in which you stir the sauce, so it doesn’t thicken too much.