This Cheesy Brussels Sprouts Casserole is tender brussel sprouts coated in a garlicky cheese sauce with mushrooms, onions, and a crispy bread crumbs topping. It’s an excellent side dish for a special occasion or just any night of the week. The whole family will love it.
If you are looking for the perfect side dish for your holiday table, this is the recipe for you. It’s simple to put together and packed with melty cheese that makes it downright crave-worthy even for picky eaters!
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Ingredients
This is a quick overview of the ingredients that you need to make this casserole. You can find the full list of ingredients and amounts in the recipe card.
- Brussels sprouts, trimmed and halved
- olive oil
- onion, finely chopped
- minced garlic
- sliced mushrooms
- dried thyme
- Salt and black pepper, to taste
- all-purpose flour
- milk (whole or 2%)
- vegetable or chicken broth
- Gruyère cheese (or your preferred melting cheese)
- grated Parmesan cheese
- breadcrumbs (Panko or regular)
- melted butter
- diced pimentos, well drained (optional)
How to Make Cheesy Brussels Sprouts Casserole
This is a quick list of the steps that are needed to make this casserole. You can find the full step-by-step instructions in the recipe card at the bottom of this post.
Cook the sprouts in boiling salted water for 5 minutes or until slightly tender. Drain and set them aside. Meanwhile, saute an onion in olive oil until translucent.
Add the minced garlic and sliced mushrooms to the skillet. Sauté for another 3-4 minutes, until the excess moisture evaporates. Stir in the thyme, salt and pepper.
Sprinkle the flour over the onion and mushroom mixture. Stir well to combine and cook for 1-2 minutes. Gradually pour in the milk and vegetable or chicken broth, stirring constantly. Cook and stir until the mixture thickens and becomes smooth.
Add the shredded Gruyère cheese to the skillet and stir until melted and incorporated into the sauce. Remove from heat.
In a separate bowl, combine the grated Parmesan cheese, breadcrumbs, and melted butter. Mix well until the breadcrumbs are evenly coated.
Add the Brussels sprouts to the cheese mixture and coat well. Transfer to a prepared baking dish and spread bread crumbs on top of the casserole. Bake in a 350-degree preheated oven for 20-25 minutes.
Hint: This casserole can stick, so make sure that you grease your baking dish well. I prefer to use nonstick cooking spray, but you could also use butter or vegetable shortening to grease it as well.
Variations and Substitutions
- Bacon – Cooked bacon or bacon bits can be added to the creamy sauce to add a little more flavor.
- Caramelized Onions – Instead of sauteed onions, you can add caramelized onions instead, they will add a touch of sweetness to this cheesy casserole.
- Cheese – Not a fan of gruyere cheese? Use any type of cheese that melts well, mozzarella cheese, white cheddar cheese or Monterey jack would work well in this rich cheese sauce.
If you are looking for another family-favorite side dish for your holiday dinner, check out this Slow Cooker Potatoes Au Gratin recipe.
Equipment
- 9×13 casserole dish or 3 quart round baking dish
- large skillet – one with a heavy bottom will work best.
Storage
- Storage – Store leftover casserole in an airtight container or cover your baking dish tightly with plastic wrap and place it in the fridge. It can be stored for 3-4 days.
- Reheating – I prefer to reheat this delicious casserole in the oven at 350°F for about 15-20 minutes. You can also microwave it, just make sure to heat it slowly in 30-second increments and stir it often so that it doesn’t get dry.
Wendy’s Test Kitchen Tips
- You can use frozen brussels sprouts for this recipe, however, you will need to steam them first. I recommend that you steam them for half the time on the bag, as you don’t want to overcook them.
- For the best melted cheese use freshly shredded cheese. The pre-shredded cheese has an anti-caking agent on it, which can hinder the melting process.
- When reheating your leftovers if you find that the casserole is a little dry, add a splash of heavy cream or milk to the sides of the casserole to help thin out the sauce.
- Reheating in the oven is the best way to get a crispy topping again. If you microwave the leftovers your topping will be soggy.
FAQ
Look for tight, compact heads and bright green leaves. Avoid any that are yellow or have droopy leaves.
It’s Brussels sprouts because they are named after the city in Belgium.
Related
Looking for other recipes like this? Try these:
Pairing
These are my favorite dishes to serve with this Cheesy Brussels Sprouts recipe. They will all work great on your Thanksgiving dinner table.
Cheesy Brussels Sprouts Casserole
Equipment
- 3 quart casserole dish or 9×13 casserole dish
- large skillet
Ingredients
- 1 pound Brussels sprouts trimmed and halved
- 2 tablespoons olive oil
- 1 onion finely chopped
- 2 cloves garlic minced
- 1 cup mushrooms sliced
- 1 teaspoon dried thyme
- Salt and pepper to taste
- 2 tablespoons all-purpose flour
- 1 cup milk whole or 2%
- 1 cup vegetable or chicken broth
- 1 cup shredded Gruyère cheese or your preferred melting cheese
- ½ cup grated Parmesan cheese
- 1 cup breadcrumbs Panko or regular
- 2 tablespoons butter melted
- 2 tablespoons diced pimentos well drained (optional)
Instructions
- Preheat the oven to 375°F (190°C). Grease a baking dish (9×13 inches or round 3 quart casserole) and set aside.
- Bring a large pot of salted water to a boil. Add the Brussels sprouts and cook for about 5 minutes, or until slightly tender. Drain and set aside.
- In a large skillet, heat olive oil over medium heat. Add the chopped onion and cook until translucent, about 3-4 minutes.
- Add the minced garlic and sliced mushrooms to the skillet. Sauté for another 3-4 minutes, until the mushrooms are cooked and any excess moisture has evaporated.
- Stir in the dried thyme, salt, and pepper to taste.
- Sprinkle the flour over the onion and mushroom mixture. Stir well to combine and cook for 1-2 minutes, allowing the flour to cook and eliminate the raw taste.
- Gradually pour in the milk and vegetable or chicken broth, stirring constantly. Cook and stir until the mixture thickens and becomes smooth, about 3-4 minutes.
- Add the shredded Gruyère cheese to the skillet and stir until melted and incorporated into the sauce. Remove from heat.
- In a separate bowl, combine the grated Parmesan cheese, breadcrumbs, and melted butter. Mix well until the breadcrumbs are evenly coated.
- In a large bowl, gently stir together the blanched Brussels sprouts, pimentos, and cheese sauce. Transfer the combination to the prepared baking dish.
- Sprinkle the breadcrumb mixture over the top of the casserole.
- Bake in the preheated oven for about 20-25 minutes, or until the casserole is bubbly and the top is golden brown.
- Remove from the oven and let it rest for a few minutes before serving.
Notes
- You can use frozen brussels sprouts for this recipe, however, you will need to steam them first.
- I recommend that you steam them for half the time on the bag, as you don’t want to overcook them.
- For the best melted cheese use freshly shredded cheese. The pre-shredded cheese has an anti-caking agent on it, which can hinder the melting process.
- Reheating in the oven is the best way to get a crispy topping again. If you microwave the leftovers your topping will be soggy.
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