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This Brussels sprout casserole with bacon is about to change how you feel about Brussels sprouts! It’s creamy, cheesy, loaded with crispy bacon, and topped with those addictive French’s fried onions.
Try our Longhorn Steakhouse Brussels Sprouts or Roasted Brussels Sprouts with Honey and Balsamic Vinegar next.
Why you’ll love it
We used to be a Brussels sprouts skeptic. But this casserole? It’s a total game-changer. The creamy Gruyère sauce makes them irresistible, and the bacon and crispy onions seal the deal.
This is the side dish that converts people at Thanksgiving and Christmas. We’ve had multiple friends ask for the recipe after just one bite, and we’ve seen kids go back for seconds!
The best part is it’s elegant enough for holiday tables but easy enough for weeknight dinners. Plus, you can prep it ahead and just pop it in the oven when ready.
What you’ll need
- Brussels sprouts – look for firm, bright green ones. You’ll need about 2 pounds, which sounds like a lot but they shrink when cooked.
- Bacon – the star player here. It adds smoky, salty goodness throughout. We use regular bacon, not thick-cut.
- Butter and bacon fat – this combo is flavor heaven. Don’t skip the bacon fat!
- Yellow onion – adds sweetness and depth to the creamy sauce.
- Garlic and red pepper flakes – for that perfect aromatic kick. The red pepper flakes add just a hint of warmth.
- All-purpose flour – this makes the roux that thickens our sauce.
- Chicken broth and heavy cream – the base of our rich, velvety sauce.
- Gruyère cheese – nutty and melty. You could also use smoked Gouda for a different flavor profile.
- Parmesan cheese – use freshly grated for the best melt and flavor.
- French’s crispy fried onions – yes, the ones from green bean casserole! They’re iconic for a reason.
Helpful Tips
- Don’t skip parboiling the Brussels sprouts. This ensures they’re perfectly tender and not crunchy in the final dish.
- Save that bacon fat! It’s liquid gold for building flavor in the sauce.
- Use freshly grated Parmesan, not the stuff in the green can. It melts so much better and tastes infinitely more delicious.
How to make Brussels sprout casserole with bacon
This is an overview with step-by-step photos. Full ingredients & instructions are in the recipe card below.
The process is easier than you’d think! You’ll start by parboiling the Brussels sprouts to get them tender, then cook up that crispy bacon.
The real magic happens when you make a creamy roux-based sauce with the bacon fat, butter, onions, and garlic—it’s basically like making a homemade cheese sauce, but better.
Once your sauce is silky and thick, you’ll fold in the Brussels sprouts and half the bacon, transfer everything to a baking dish, and top it with Gruyère and Parmesan.
After 20 minutes in the oven, you’ll add those iconic crispy fried onions and the rest of the bacon for the final 5 minutes. The result? Bubbly, golden, absolutely irresistible.
Substitutions and variations
- Use smoked Gouda instead of Gruyère for an extra smoky flavor. Or try sharp white cheddar if that’s what you have!
- Make it vegetarian by skipping the bacon and using olive oil instead of bacon fat. Add some smoked paprika to achieve that smoky depth.
- Swap Brussels sprouts for broccoli or cauliflower if that’s your thing. Same cooking method applies.
- Add some chopped pecans or panko breadcrumbs to the topping for extra crunch.
- For a lighter version, use half-and-half instead of heavy cream. It won’t be quite as rich, but still delicious.
What to serve with Brussels sprout casserole
This is our go-to Thanksgiving and Christmas side dish. It pairs perfectly with roasted turkey, honey-glazed ham, or prime rib.
Serve it alongside our Boursin Mashed Potatoes or Creamy Garlic Mashed Potatoes for a complete holiday spread.
It’s also fantastic with Lemon and Garlic Roast Chicken for a weeknight dinner that feels special.
Make ahead instructions
- You can assemble this casserole up to 24 hours ahead! Prepare everything through step 10 (before baking), cover tightly with foil, and refrigerate.
- When ready to bake, let it sit at room temperature for 20-30 minutes, then bake as directed. You may need to add 5-10 minutes to the baking time since it’s coming from the fridge.
- Add the crispy onions and remaining bacon only in the last 5 minutes—this keeps them crunchy!
Leftovers and storage
Store leftovers in an airtight container in the fridge for up to 4 days.
Reheat in the oven at 350°F until warmed through, about 15-20 minutes. You can also reheat individual portions in the microwave, but the oven keeps the onions crispier.
We don’t recommend freezing this casserole. The cream sauce and Brussels sprouts don’t freeze particularly well, and you’ll lose that crispy topping texture.
❓FAQs
Yes! This step is important. Raw Brussels sprouts won’t cook through properly in the oven during the baking time, and you’ll end up with crunchy, undercooked sprouts instead of tender ones.
Fresh is best for this recipe, but if you must use frozen, thaw them completely and pat them very dry before using. Skip the parboiling step since they’re already partially cooked.
Smoked Gouda, sharp white cheddar, fontina, or even Swiss cheese work great! Pick something that melts well and has good flavor.
Absolutely! Assemble everything except the crispy onions and final bacon topping. Cover and refrigerate overnight. Let it come to room temperature for 20-30 minutes before baking, and add a few extra minutes to the baking time.
Cut off the tough stem end and remove any yellowed or damaged outer leaves. Then slice them in half lengthwise. They should look clean and bright green.
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Brussels Sprout Casserole with Bacon
Ingredients
- 2 pounds Brussels sprouts, washed, trimmed, and halved
- 8 slices bacon, chopped
- 2 tablespoons unsalted butter
- 1 medium yellow onion, finely diced (about 1 cup)
- 4 teaspoons minced garlic
- ½ teaspoon crushed red pepper flakes
- ¼ cup all-purpose flour
- 1 cup chicken broth
- 1 cup heavy whipping cream
- 1 teaspoon kosher salt
- ½ teaspoon black pepper
- 1 cup shredded Gruyère cheese, or Smoked Gouda
- 1 cup freshly grated Parmesan cheese
- 1½ cups French’s crispy fried onions
- Fresh parsley, chopped, for garnish
Instructions
- Prep the Oven & Dish: Preheat oven to 400°F (200°C). Lightly grease a 9×13-inch baking dish and set aside.
- Parboil the Brussels Sprouts: Bring a large pot of salted water to a boil. Add Brussels sprouts and cook 4–5 minutes until just fork-tender. Drain well and set aside.
- Cook the Bacon: In a large skillet over medium heat, cook the chopped bacon until crispy. Remove with a slotted spoon and set aside, leaving 2 tablespoons of bacon fat in the pan (discard extra).
- Sauté the Aromatics: Add the butter to the skillet with the bacon fat. Once melted, stir in the diced onion and cook 3–4 minutes until softened.
- Add the garlic and crushed red pepper flakes; cook 30 seconds until fragrant.
- Make the Roux: Sprinkle flour over the onion mixture. Stir constantly for 1 minute to cook out the raw flour taste.
- Build the Creamy Sauce: Slowly whisk in the chicken broth, scraping up any browned bits. Cook 1–2 minutes until slightly thickened.
- Pour in the heavy cream and whisk 2–3 minutes until smooth, creamy, and thick enough to coat a spoon. Season with salt and pepper.
- Add the parboiled Brussels sprouts and half of the cooked bacon, gently folding until evenly coated.
- Assemble the Casserole: Transfer the mixture to the prepared baking dish.
- Sprinkle Gruyère and Parmesan evenly over the top.
- Bake uncovered for 20 minutes, until bubbly and golden around the edges.
- Add Crunch: Remove from oven and sprinkle French’s crispy fried onions and the remaining cooked bacon over the top.
- Return to the oven for 5 minutes, just until crisp and lightly toasted.
- Let the casserole rest for 5 minutes. Garnish with fresh parsley and serve warm.
Notes
- Don’t skip the parboiling! This step ensures your Brussels sprouts are perfectly tender in the finished dish. Undercooked sprouts are no fun.
- Use freshly grated cheese: Pre-shredded cheese has anti-caking agents that prevent smooth melting. Grate your own for the creamiest, most luscious sauce.
- Add crispy toppings at the end: The fried onions and final bacon go on in the last 5 minutes so they stay crunchy, not soggy.
- Let it rest: Those 5 minutes after baking help the sauce thicken up and make serving easier.
- Make ahead: Assemble everything up to the baking step, cover, and refrigerate for up to 24 hours. Add the crispy onions and bacon only in the last 5 minutes of baking.
- Cheese swaps: Gruyère is our favorite, but smoked Gouda, fontina, or sharp white cheddar all work beautifully.
- Make it vegetarian: Skip the bacon and use 3 tablespoons butter or olive oil instead. Add smoked paprika for that smoky depth.
- Storage: Store leftovers in an airtight container in the fridge for up to 4 days. Reheat in a 350°F oven for best results.
- Don’t freeze: This casserole doesn’t freeze well due to the cream sauce and Brussels sprouts texture.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
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Absolutely delicious! Even my kids, who usually avoid Brussels sprouts, went back for seconds. The creamy sauce and crispy bacon made it irresistible.
That’s amazing, Amanda! 🥰 So glad your kids enjoyed it too — the bacon magic works every time! Thanks for giving it a try.
Made this for yesterday’s dinner and everyone loved it!
Thank you, Chloe! 😊 I’m so glad it was a hit at dinner. The crispy bacon really makes it extra special!
I never thought Brussels sprouts could taste this good. The bacon added so much flavor and everyone loved it.
Isabella, Brussels sprouts with bacon are a magical combo! I’m happy it converted you.
This is a great way to get people who don’t love Brussels sprouts to enjoy them.
That’s one of my favorite things about this recipe, Daniel. It really wins people over!