One of my favorite holiday side dishes is Brussels Sprouts Au Gratin! The Brussels sprouts are oven-roasted, and then coated with a cheesy sauce and baked with melty Gruyere and Parmesan cheese. It’s also got bacon bits to make it extra delicious! You will love it.
I am a Brussels sprouts lover. I especially like them oven-roasted because roasting brings out so many delicious flavors. So, for this Brussels Sprouts Au Gratin recipe, I roasted the Brussels sprouts and then baked it with a creamy cheese sauce and melty cheese on top. So delicious!
If you love Brussels sprouts and gooey cheese, you will seriously love this Brussels sprouts au gratin. Plus, it’s very easy to make and reheats very well. It’s like a dream come true!
I tested and tweaked this Brussels sprouts gratin recipe several times, and I promise it’s REALLY GOOD! I’m sharing the recipe below, including tips to prep this dish ahead.
Ingredients You’ll Need
I love all the ingredients in this Brussels sprouts au gratin. A lot of flavor and richness going here!
Here is an overview of the ingredients you’ll need (quantities in the recipe card below):
- Brussels sprouts: Trimmed and halved lengthwise.
- Minced garlic: For flavor.
- Unsalted butter: To make a roux along with the flour. This will be the thickener for the cheese sauce.
- All-purpose flour: Same as the above, to make the roux.
- Whole milk or 2 percent milk: For the sauce. Don’t use skim milk, as it can be too diluted.
- Grated gruyere cheese: For the cheese sauce and the topping.
- Shredded Parmesan cheese: For the topping.
- Cooked bacon: Crumbled. You can also use cubed ham.
- Salt, pepper, and olive oil
Let’s Make It
There are basically 3 parts to make Brussels sprouts au gratin:
- Roast the Brussels sprouts: I roast them at 400 degrees Fahrenheit with minced garlic, salt, pepper, and olive oil. About 20 minutes should be enough so soften them without turning them mushy. Remember, they need to bake for an additional 15 minutes along with the cheese.
- Make the cheese sauce: Make a roux by cooking equal parts of butter and flour. This will be the thickener. Then add milk and cheese to make the creamy and cheesy sauce.
- Assemble and bake: Toss the roasted Brussels sprouts with the cheese sauce and the cooked bacon bits. Transfer to a baking dish and top with more cheese. Bake until bubbly and golden brown.
As always, the specific instructions are detailed in the recipe card below. These Brussels sprouts au gratin are seriously delicious, cheesy, and melty! So easy to make and prep-ahead friendly too.
Make Ahead Tips
- Cook the bacon and up to 2 days in advance, and refrigerate.
- Trim and halve the Brussels sprouts.
- Shred or grate the cheeses. Use a box grater, or a food processor if it has the blades for grating.
- Make the cheese sauce up to 1 day in advance, and refrigerate. Prior to using, warm it up in a saucepan first.
- Shortcuts: Use pre-packaged bacon bits.
Cheeses You Can Use
For both the cheese sauce and the topping, you can customize it with your favorite cheese, as long as they are the kind that melt very well. And of course, you can mix and match various cheeses too.
I’d recommend getting chunks of cheese and grating it yourself with a box grater. This way, the cheese will melt a lot better as pre-packaged cheese usually comes with other ingredients that make it harder to melt.
Here are a few of my favorite cheese to use in this Brussels sprouts au gratin:
- White cheddar
So easy, delicious, and cheesy! You will love these Brussels sprouts au gratin. They are tender, melty, and full of so much flavor. Plus, it’s a prep ahead friendly recipe.
I will for sure be making it for the holidays. In fact, I’m going to be making a double batch because, knowing my family, these will be gone in a matter of seconds!
My favorite holiday and fall-inspired side dishes:
- Stuffed Acorn Squash with Rice Pilaf and Mushrooms
- Brussels Sprouts and Butternut Squash Salad
- Fall Harvest Salad
- White Cheddar Mac and Cheese
- Red Skin Mashed Potatoes
Thanks for reading! I hope you like this recipe as much as I do. Happy cooking!
Tips for Success
- Grate your own cheese so it melts really well. Most of the time, pre-packaged grated cheese comes with extra preservatives that make it hard to melt.
- The cheese sauce can be made the day before. Warm it up in a saucepan before using.
- Other prep-head friendly things: cook and crumble the bacon, trim and halve the Brussels sprouts, shred the cheese.
- If you want it extra golden brown, broil it for 1-2 minutes at the end.
Brussels Sprouts Au Gratin
- 1.5 pounds fresh Brussels sprouts, trimmed and halved lengthwise
- Salt and pepper
- 3 cloves garlic, minced
- Olive oil
- 2 tablespoons unsalted butter
- 2 tablespoons all-purpose flour
- 1 ¼ cups whole milk (plus more as needed)
- 1 cup shredded or grated Gruyere cheese, divided
- ½ cup shredded parmesan cheese
- ⅓ cup crumbled cooked bacon (plus more for garnish)
Roast the Brussels Sprouts
- Preheat oven to 400 degrees Fahrenheit.
- On a large sheet pan, toss the Brussels sprouts with the minced garlic, a few drizzles of olive oil, about ¼ teaspoon of salt, and a few grinds of black pepper. Roast for 20 minutes at 400 degrees Fahrenheit, flipping halfway through. Tip: Don't overcrowd the pan. Use two sheet pans if needed.
Make the Cheese Sauce
- Meanwhile, make the cheese sauce. In a medium pot, melt the butter over medium heat. Once melted, add the flour and whisk constantly for about 3-4 minutes, until thickened. This is called a roux. At this point, it should be a bit pale in color and begin to smell a tiny bit toasty.
- Then, gradually add the milk, breaking up the roux with a wooden spoon. Simmer for a few minutes until thickened.
- Add ½ cup of the gruyere cheese and stir until melted. Add more milk if needed until desired consistency. Season with salt and pepper to taste. Turn off the heat.
Assemble and Bake
- Toss the roasted Brussels sprouts with the cheese sauce and the bacon until combined. Transfer to a baking dish. Sprinkle with the remaining ½ cup of gruyere cheese, the parmesan cheese, and more bacon bits.
- Bake at 400 degrees Fahrenheit for 15-18 minutes until bubbly and golden brown. If desired, broil for 1-2 minutes additional minutes to get a deeper golden brown color. Serve immediately. Enjoy!
- Special equipment: box grater, baking dish, sheet pans.
- Make ahead: Cook the bacon in advance. Trim and halve the Brussels sprouts in advance. Grate or shred the cheese in advance. Make the cheese sauce 1 day ahead.
- Cheese sauce: It can be made 1 day in advance. Refrigerate, and warm it up in a saucepan prior to using.
- Storing: Refrigerate for up to 3 days. Reheat in the microwave oven.