This extra-cheesy Brussels Sprouts Gratin is a must for Thanksgiving! Thinly sliced brussels sprouts are tossed in a creamy gruyere sauce and topped with buttery breadcrumbs. The end result is an over-the-top delicious gratin that even the staunchest brussels sprouts skeptics will love!
“This one was a hit at Thanksgiving dinner! I opted to blanch and drain the brussels before hand (this helped remove excess moisture from the sprouts and make sure they were super soft when they came out of the oven.) This dish was a hit, even with my kids!” – Dustin, So Much Food reader
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It’s Impossible to Hate Brussels Sprouts When They’re Coated in Cheese!
When I set out to create my Thanksgiving menu this year, I knew I wanted to include a brussels spouts recipe. What I didn’t expect was for this recipe to be an absolute hit that people raved over!
Brussels sprouts can be polarizing, but even veggie skeptics won’t be able to resist this ultra-cheesy and decadent casserole. Brussels sprouts gratin is a deceptively simple recipe and only requires 9 ingredients! You can prep it in advance or throw it together last minute.
While this recipe is perfect served alongside Thanksgiving turkey, mashed potatoes, and gravy, you can just as easily serve it with roast chicken for an easy weeknight side dish.
Ingredients (with Substitutions)
You can find the full list of ingredients, quantities & method in the recipe card at the end of the page.
- Brussels sprouts. I buy the pre-shredded sprouts in the refrigerated section! This is my favorite hack for this recipe because it’s such a time-saver. You can find shaved brussels sprouts at HEB, Target, Sprouts, Trader Joe’s, etc. You can also shred them yourself with a mandoline or with a sharp knife.
- Butter + flour. The gratin is thickened with a roux made with butter and flour.
- Half and half. I love the richness that half and half adds. You could use whole milk if needed, but I think the extra fat makes all the difference!
- Shallot. I love the mellow onion flavor of shallots. You could also use yellow onion if needed.
- Garlic. Fresh garlic is a must!
- Cheese. A mix of gruyere and parmesan is the perfect blend of melty, salty, savory, and a bit nutty that pairs so well with the brussels sprouts.
- Dijon. A little bit of dijon adds great savory notes to the gratin.
- Nutmeg. A pinch of fresh nutmeg in the sauce is classic! You can omit it if desired.
- Breadcrumbs. I love using fresh breadcrumbs, but you can also use panko.
Want to make your own breadcrumbs? Whenever I have bread that’s getting ready to go stale or that’s been hanging around for a bit, I make a batch of breadcrumbs to keep in the freezer. Simply tear some pieces of bread into chunks and throw them into a food processor and run it until you have small crumbs. It’s THAT easy. Store in a freezer-safe ziplock bag in the freezer for up to 6 months.
Useful Tools for This Recipe
- Braiser or Skillet
- Sharp Knife or Mandoline
- Cutting Board
- Mixing Bowl
How to Make Brussels Sprouts Gratin
Jenny’s Tip; I love making this creamy brussels sprouts gratin in a braiser or oven-safe skillet so that I can make everything in one pan that goes directly from stovetop to oven to table.
- Make the roux. “Roux” sounds so fancy, but really it’s just flour that’s been sprinkled into some melted butter and cooked for 2 – 3 minutes until the raw flour flavor disappears and a paste forms.
- Make the béchamel sauce. Slowly whisk the half and half into the roux and bring to a gentle simmer. The mixture will be lumpy for a while, but as the dairy warms and you keep whisking the cream sauce will smooth out.
- Stir in the cheeses off the heat. The reason we remove the pan from the heat first is to prevent the sauce from splitting.
- Season the breadcrumbs. To the breadcrumbs, mix in a little extra Parm, salt, and pepper. Then, toss with melted butter (this helps the breadcrumb topping get super crispy).
- Assemble and bake. Stir the brussels sprouts into the béchamel sauce, then top with breadcrumbs. Bake at 400ºF until the topping is golden brown and the edges are bubbling.
Make Ahead Instructions
When you’re hosting a large dinner or event (especially Thanksgiving), I am definitely team prep ahead! Any recipe that can be made early will be made early so that the big day goes off without a hitch.
- Follow the recipe up until you stir the cheeses into the bechamel.
- Let the sauce cool for 15 minutes, then stir in the shaved brussels sprouts.
- Transfer the mixture to a greased baking dish and cover tightly with plastic wrap. Refrigerate overnight.
- When it’s time to cook, top with the remaining cheese and the breadcrumbs and bake at 375ºF for 25 minutes. Make sure the gratin is warmed through!
If you do give this recipe a try, be sure to let me know! Leave a comment with a star rating below. Be sure to subscribe to my weekly newsletter and never miss a new recipe! You can also snap a photo & tag @JENNYGOYCOCHEA on Instagram. I LOVE hearing about & seeing your SMF creations!
More Thanksgiving Side Dish Recipes
- Orange Cinnamon Cranberry Sauce
- Brioche Dinner Rolls
- Baked Cream Cheese Mac and Cheese
- Horseradish Mashed Potatoes
- Homemade Green Bean Casserole
- Cornbread Stuffing with Bacon
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Cheesy Brussels Sprouts Gratin Recipe
Ingredients
Brussels Sprouts Gratin
- 3 tablespoons unsalted butter
- 2 shallots, diced
- 2 garlic cloves, thinly sliced
- 3 tablespoons all-purpose flour
- 3 cups half and half, warmed slightly
- 1 teaspoon dijon mustard
- 1/8 teaspoon freshly grated nutmeg
- 1 1/4 cup shredded gruyere cheese
- 1/3 cup freshly grated parmesan cheese
- 1 lb brussels sprouts, trimmed and shaved
- kosher salt
- freshly cracked black pepper
Breadcrumb Topping
- 1 cup fresh or panko breadcrumbs
- 1/3 cup freshly grated parmesan cheese
- 3 tablespoons butter, melted and cooled
Instructions
- Preheat an oven to 400ºF.
- Make the roux. Melt the butter in an oven-safe skillet or braiser over medium heat. Add the shallots and garlic and cook for 2 minutes, until fragrant. Sprinkle in the flour and stir well to form a paste. Cook, stirring constantly, for 2 minutes to cook out the raw flour.
- Make the sauce. Pour in the warmed half and half while whisking, until smooth. Bring to a gentle simmer while whisking until thickened. Add the dijon and nutmeg and stir well. Remove from the heat and stir in the gruyere and parm until melted. Season to taste with salt and pepper.
- Season the breadcrumbs. Mix the breadcrumbs and parmesan together in a small mixing bowl and toss with the melted, cooled butter. Season with salt and pepper.
- Assemble the gratin. Stir the shaved brussels sprouts into the cheesy bechamel sauce until everything is well-mixed and coated. Season with a bit more salt and pepper and top with the breadcrumb mixture.
- Bake. Transfer the skillet to the oven and bake for 20 minutes, until the top is browned and the cheese is melted and bubbly. Cool for 15 minutes before serving.
Storage
- Leftovers can be stored in an airtight container in the fridge for 3-5 days. I don't recommend freezing this gratin as the brussels sprouts get mushy when defrosted. I recommend reheating in the oven vs the microwave to give the breadcrumbs some of their crispness back.
Rate & Review This Recipe
This one was a hit at Thanksgiving dinner! I opted to blanch and drain the brussels before hand (this helped remove excess moisture from the sprouts and make sure they were super soft when they came out of the oven.) This dish was a hit, even with my kids!
So happy you and your family loved it!