Cheesy Brussels Sprouts Casserole

Hot, bubbly and deliciously decadent, my cheesy Brussels sprouts casserole is an extra cozy side dish, and a tasty new way to enjoy your Brussels sprouts. Prepared with roasted Brussels sprouts, caramelized leeks, bacon, a creamy Gruyere and white cheddar cheese sauce and crispy-fried onions, this scrumptious Brussels sprouts casserole is a terrific pick for the holiday table, or any night of the week!

A Delectably Cheesy Way to Enjoy Brussels Sprouts

One of my favorite things about being a recipe developer is coming up with tasty ways to get us all to enjoy our veggies, big kids and little kids alike!

While Brussels sprouts may be a beloved cruciferous veg for many of us, there are those that find these little green globes a little too “cabbage-y”, or a bit too plain to really enjoy.

But sometimes, all it takes is a little added decadence, a few bells and whistles mixed in to entice even the most veggie-averse among us to want to grab their fork and dig in!

My cheesy Brussels sprouts casserole is a fantastic pick as a side dish fit for the holiday table as well as dinner any night of the week.

It will delight those of us who don't need convincing to eat these yummy green sprouts, and even those who may need a gentle little nudge (you know who you are!).

Prepared with roasted Brussels sprouts, caramelized leeks, crispy bacon, plus a rich and creamy sauce brimming with a combo of Gruyere and sharp white cheddar cheese, and a crispy-fried onion topping, this Brussels sprout casserole recipe will surely have everyone coming back for a second helping!

My Recipe for Cheesy Brussels Sprouts Casserole

One thing that I really appreciate about Brussels sprouts is that they are terrific little canvases that partner with other earthy ingredients, and take on other flavors really well.

In my mind, bacon and Brussels sprouts are natural partners (and you can see this combo together in my Brussels sprout soup with bacon), with leeks fitting into that equation really well too. So I'm keeping things simple by combining those three ingredients with a cheesy sauce that's filled with savory flavor and creamy richness...

For this cheese sauce, I'm using a combination of both Gruyere and sharp white cheddar for flavor and deliciously meltable texture. I'm also adding a touch of garlic and a kiss of Herbes de Provence to round out the flavor, then folding it all together with the Brussels sprouts, leeks and bacon, coating everything completely in the deliciousness.

Of course, a cheesy casserole such as this needs a crispy topping, so I'm opting for flavorful crispy-fried onions, sprinkling them over top of the casserole—so savory and so tasty!

Here's a glance at my cheesy Brussels sprouts casserole recipe: (or just jump to the full recipe...)

1. To get started, I roast off my Brussels sprouts just until tender.
2. Next, I caramelize my leeks in a skillet until golden-brown.
3. Then, I prepare my simple cheese sauce, and keep that warm.
4. To prep the casserole, I combine the Brussels sprouts, bacon, and leeks with the cheese sauce, spoon into my prepared casserole dish, and top with a touch more cheese.
5. I bake for about 20 minutes, then sprinkle over my crispy-fried onions, and then bake 5 minutes more.
6. I serve the casserole immediately after baking, sprinkled with fresh thyme.

Recipe

Cheesy Brussels Sprouts Casserole

by Ingrid Beer

Print Recipe

This cheesy Brussels sprouts casserole is brimming with leeks, bacon, and creamy sauce kissed with Gruyere and sharp white cheddar cheese!

Category: Side
Cuisine: American

Yield: Serves 8

Nutrition Info: 354 calories per serving

Prep Time: 25 minutes
Cook time: 55 minutes
Total time: 1 hour, 20 minutes

Ingredients:

• 2 ½ pounds Brussels sprouts, halved (or quartered, if very large)
• Olive oil
• Salt
• Black pepper
• 1 ½ teaspoons granulated onion, divided use
• 1 teaspoon granulated garlic
• 2 large leeks (white part only), sliced thinly into semi-circles
• 1 ½ ounces unsalted butter (3 tablespoons)
• 2 cloves garlic, pressed through garlic press
• 1 ½ ounces flour (roughly 5 tablespoons)
• 3 cups milk
• 1 teaspoon Herbes de Provence
• 1 cup grated Gruyere cheese, divided use
• 1 cup grated sharp white cheddar, divided use
• ¼ cup crumbled, crispy bacon
• ⅓ cup crispy-fried onions
• Thyme leaves or chopped chives, for garnish

Preparation:

1. Begin by gathering and prepping all of your ingredients according to the ingredients list above to have ready and organized for use.
2. Preheat your oven to 400°, and line a large baking sheet with foil. Also, prepare a 3 quart size baking dish with a spritz or two of cooking spray.
3. Add the Brussel sprouts to a large bow, and drizzle over a couple of tablespoons of the olive oil and add a couple of pinches of salt and pepper, plus 1 teaspoon of the granulated onion and the teaspoon of granulated garlic, and toss to coat. Turn the Brussels sprouts out onto the baking sheet, and roast for 25 minutes.
4. While the Brussels sprouts roast, place a medium skillet over medium-high heat, and drizzle in a couple of tablespoons of olive oil. Add the sliced leeks, a couple of pinches of salt and pepper, and caramelize the leeks just until golden-brown, about 10 minutes. Spoon into a dish to hold.
5. Next, prepare your cheese sauce by placing a medium size pot over medium heat, and adding in the butter. Once melted, add in the garlic, and stir just until aromatic, then sprinkle in the flour and stir to create of roux, or paste-like mixture. Cook the roux for about 30 seconds to a minute to cook out the raw flour taste.
6. Pour in the milk, whisking all the while to to avoid lumps from forming, then allow the sauce to gently simmer and thicken up for about 5 to 7 minutes.
7. Once thickened, remove from heat and add in about ¾ teaspoon of salt (or to your taste), about ¼ teaspoon of black pepper, the remaining ½ teaspoon of granulated onion, the Herbes de Provence, plus ¾ cup of the Gruyere cheese and ¾ cup of the white cheddar cheese. Whisk the sauce well to blend and to melt the cheese. Set the sauce aside for a moment.
8. Once the Brussels sprouts have roasted, turn the oven temp down to 350°. Then, spoon the Brussels sprouts into a large bowl, along with the leeks and the bacon, and pour in the cheese sauce as well. Using a rubber spatula, fold the mixture together until all the ingredients are creamy, and spoon into your prepared baking dish.
9. Sprinkle over the remaining ¼ cup of Gruyere and ¼ cup of sharp white cheddar cheese, and bake the Brussels sprouts casserole for 20 minutes.
10. Then, sprinkle over top the crispy-fried onions, and bake for 5 minutes more.
11. To finish, sprinkle over the fresh thyme leaves or chives and serve.

Tips & Tidbits for my Cheesy Brussels Sprouts Casserole recipe:

• Fresh, firm Brussels sprouts for best flavor: When choosing Brussels sprouts, opt for globes that are firm and green, and a medium-large size. Avoid sprouts that are rubbery or too brown or oxidized. You can remove and discolored leaves if necessary. And if the sprouts are very large, you can quarter them, otherwise simply halve them.
• Organic bacon crumbles, or pre-cooked bacon for convenience: If you can find good quality pre-cooked bacon, or organic bacon crumbles , you can opt for those and just measure out a ¼ cup. Otherwise, you can crisp up your own bacon, and chop it up to yield approximately one ¼ cup. You can also sub turkey bacon, if you prefer.
• Prepare the Brussels sprouts casserole ahead: To prep this cozy casserole ahead, simply roast your Brussels sprouts and allow them to cool, then keep them in a covered container in the fridge. You can also prep your cheese sauce and keep it in the fridge as well. The day you'd like to prepare the casserole, allow your casserole ingredients to come to room temp, then proceed with combining everything and baking the casserole according the recipe.

Hungry for more cozy recipes like this one? Check out my recipes for Brussels Sprout Soup with Bacon, Butternut Squash Casserole, green bean casserole, Spaghetti Squash Casserole, and my recipe for Baked Brussels Sprouts with Cider Glaze!