Brussels Sprouts with Cheese Sauce
Brussels Sprouts with Cheese Sauce is a cozy, flavorful side dish made with a rich Gruyère sauce and crispy bacon. This cheesy, comforting recipe is perfect for holidays, dinner parties, or weeknight meals!
Brussels Sprouts Gratin
On an ordinary day, a simple pan of roasted Brussels sprouts is more than enough as a side to a protein. But when the holidays or special occasions roll around, I like to take those same vegetables and dress them up a bit.
Brussels sprouts used to get such a bad reputation, but I’m here to say they’ve totally redeemed themselves in my kitchen. What used to be the veggie everyone pushed to the side of the plate is now one of my absolute favorites – I could eat them any night of the week! Btw, they are good cold too – eaten straight out of the container of leftovers!
Why we love this casserole:
- Bacon makes everything better—smoky, salty bites pair perfectly with tender sprouts.
- Gruyère cheese sauce is next-level—rich, nutty, and super creamy.
- Transforms Brussels sprouts into a comfort food favorite, even for picky eaters.
- Holiday-worthy but weeknight easy—fancy enough for guests, simple enough for everyday. Plus we always have something “green” on our table!
- Balanced flavors—savory bacon, nutty Gruyère, and earthy sprouts all complement each other.
- Crowd-pleasing upgrade—turns a humble veggie into a show-stopping side dish.
What You’ll Need:
- Brussels Sprouts – I started with three pounds of Brussels sprouts, but it will be less after trimming them.
- Olive Oil – Necessary for roasting the veggies.
- S&P
- Bacon – par-cooked and crumbled
- Butter – I use unsalted butter.
- Onion and Garlic
- Flour – Used to thicken the sauce.
- Whole Milk
- Cheese – Gruyere Cheese and Parmesan Cheese
- Seasonings – Thyme, salt, and pepper.
How to make Brussels Sprouts Gratin:
Step 1
Prepare the veggies. Slice the stems off the Brussels sprouts and remove the outer leaves. Slice in half or fourths, depending on size.
Step 2
Roast veggies. Place the Brussels sprouts on two baking sheets lined with parchment paper. Drizzle with olive oil, and sprinkle with kosher salt and freshly ground black pepper to taste. Roast until the veggies are fork tender and are slightly browned. (I use my convection oven when I roast veggies so I can get a nice crisp to them.)
Add the veggies to a 9×13 casserole dish.
Step 3
Grate the cheese. Freshly grate the gruyere cheese and parmesan cheese. Using pre-shredded cheese will sometimes make the melting process difficult.
Step 4
Make the cheese sauce. In a medium saucepan, sauté the chopped bacon until slightly crispy. Remove the bacon and add to the Brussels sprouts.
Use the bacon grease or add the butter to pot. Add onion and cook until softened, about 3-4 minutes. Then add garlic and stir for about 30 seconds. Add flour and whisk until it’s well combined, about one minute. Then add milk and bring to a simmer. You’ll see it thicken as you whisk.
Add seasonings – the thyme, salt and pepper. Remove from heat and stir in gruyere and parmesan cheese . Stir until completely melted. Then add the sauce over the Brussels sprouts.
Step 5
Make topping. Combine the melted butter, bread crumbs, parmesan cheese, and dried thyme. Add over top of the cheese sauce.
Step 6
Bake casserole. Bake Brussels sprouts with cheese sauce for 20-25 minutes, or until piping hot.
Store leftover casserole in an airtight container in your refrigerator for 3-4 days. Reheat to serve.
Recipe FAQs:
Yes, you can prep it early. Prepare the gratin but don’t bake until right before serving. You’ll need to increase the bake time to about 45 minutes to get everything nice and hot. Cover with foil if the bread crumb topping starts to get too dark on top. Casserole leftovers are GREAT!
To prep Brussels sprouts, trim the end off each one. Then remove the outer leaves. Slice them in half or fourths, depending on the size of the veggies.
A gratin is a technique in which an ingredient is topped with a browned crust, often using cheese or breadcrumbs, sometimes both. (Easy but fancy, right?)
Tips for Roasting Vegetables:
- Chop veggies in similar size so that roasting time is accurate for the whole batch.
- If mixing veggies, chop quicker cooking ones larger and slower cooking ones smaller.
- Spray the baking sheet with spray (or line it with parchment paper).
- Spread veggies in pan without crowding them. This will ensure they are roasted and not steamed.
- Use a nice amount of olive oil (good fats!) and salt & pepper (or other seasonings you prefer).
- Roast your vegetables until they are fork tender, and slightly charred.
If you need a couple of salads (aka dessert salad!) on your menu, try our Snicker Salad Recipe or Raspberry Pretzel Salad too!
Kitchen Tools Used: (affiliate links)
xoxo ~Sue
Brussels Sprouts with Cheese Sauce
Ingredients
For the veggies:
- 2 ½ pounds Brussels sprouts – AFTER stems and leaves removed
- 3 Tablespoons olive oil
- kosher salt and freshly ground black pepper – to taste
For the sauce:
- 4-5 slices bacon – par-cooked and crumbled
- unsalted butter – use bacon grease OR 3 tablespoons butter
- 1 cup white onion – diced
- 3 cloves garlic – minced
- 3 Tablespoons all-purpose flour
- 2 ½ cups whole milk
- 8 oz. gruyere cheese – freshly grated
- 1/2 cup parmesan cheese – freshly shredded
- kosher salt and freshly ground black pepper – to taste
For the topping:
- 2 Tablespoons unsalted butter
- 1 cup Panko breadcrumbs
- 1/4 cup parmesan cheese
- 1 teaspoon dried thyme
Instructions
- Prepare the veggies. Slice the stems off the Brussels sprouts and remove the outer leaves. Slice in half or fourths, depending on size.
- Roast veggies. Place the Brussels sprouts on two baking sheets lined with parchment paper. Drizzle with olive oil, and sprinkle with kosher salt and freshly ground black pepper to taste. Roast until the veggies are fork tender and are slightly browned. (I use my convection oven when I roast veggies so I can get a nice crisp to them.)Add the veggies to a 9×13 casserole dish.2 ½ pounds Brussels sprouts, 3 Tablespoons olive oil, kosher salt and freshly ground black pepper
- Grate the cheese. Freshly grate the gruyere cheese and parmesan cheese. Using pre-shredded cheese will sometimes make the melting process difficult.
- Make the cheese sauce. In a medium saucepan, sauté the chopped bacon until slightly crispy. Remove the bacon and add to the Brussels sprouts.Use the bacon grease or add the butter to pot. Add onion and cook until softened, about 3-4 minutes. Then add garlic and stir for about 30 seconds. Add flour and whisk until it’s well combined, about one minute. Then add milk and bring to a simmer. You’ll see it thicken as you whisk.Add seasonings – salt and pepper. Remove from heat and stir in gruyere and parmesan cheese . Stir until completely melted. Then add the sauce over the Brussels sprouts.4-5 slices bacon, (unsalted butter), 1 cup white onion, 3 cloves garlic, 3 Tablespoons all-purpose flour, 2 ½ cups whole milk, 8 oz. gruyere cheese, 1/2 cup parmesan cheese, kosher salt and freshly ground black pepper,
- Make topping. Combine the melted butter, bread crumbs, parmesan cheese, and dried thyme. Add over top of the cheese sauce.2 Tablespoons unsalted butter, 1 cup Panko breadcrumbs, 1/4 cup parmesan cheese, 1 teaspoon dried thyme
- Bake casserole. Bake Brussels sprouts with cheese sauce for 20-25 minutes, or until piping hot.
Awesome recipe! I love it.
Thank you!