Pin This creamy Brussels sprouts gratin transforms the often-divisive vegetable into an irresistible side dish that even skeptics will love. The tender sprouts are enveloped in a rich, cheesy sauce and topped with a golden, crispy crust that provides the perfect textural contrast.
I first made this gratin for Thanksgiving when I needed a vegetable dish that would please both Brussels sprout lovers and haters alike. The empty dish and requests for the recipe confirmed it was a winner, and it's now my go-to method for converting Brussels sprout skeptics.
Ingredients
- Brussels sprouts: These little cabbage-like vegetables become sweet and tender when properly cooked. Look for firm, bright green sprouts with tightly packed leaves for the freshest flavor.
- Unsalted butter: Creates a rich base for the sauce and adds golden color to the topping. Using unsalted allows you to control the overall salt level.
- Garlic and onion: These aromatics build a flavorful foundation. Choose firm garlic cloves without green sprouts and a sweet yellow onion.
- Heavy cream and whole milk: The combination provides creaminess while keeping the sauce from becoming too heavy. Full-fat dairy products yield the best texture.
- Dijon mustard: Adds a subtle tangy note that balances the richness. Traditional Dijon works best for its smooth texture and complex flavor.
- Nutmeg: This warming spice complements creamy sauces beautifully. Freshly grated nutmeg offers the most vibrant flavor.
- Gruyère and Parmesan cheeses: Gruyère melts beautifully with a nutty flavor, while Parmesan adds savory depth. Always grate your own for superior melting and flavor.
- Fresh breadcrumbs: Creates an irresistible crispy topping. Making your own from day-old bread yields the best texture.
- Fresh parsley: Optional but adds a pop of color and freshness to finish the dish.
Instructions
- Prepare the Brussels sprouts:
- Bring a large pot of generously salted water to a rolling boil. Add halved Brussels sprouts and blanch for exactly 4-5 minutes until barely tender when pierced with a knife. They should still have some resistance as they'll continue cooking in the oven. Immediately drain and rinse with cold water to stop the cooking process. This prevents them from becoming mushy in the final dish.
- Create the flavor base:
- Melt butter in a large skillet over medium heat until it begins to foam slightly. Add the finely chopped onion and cook for 3 minutes, stirring occasionally, until they become translucent but not browned. Add the minced garlic and cook for just 1 minute more until fragrant. Be careful not to let the garlic brown or it will become bitter.
- Make the cream sauce:
- Pour in the heavy cream and milk, stirring constantly to combine with the aromatics. Add the Dijon mustard and nutmeg, whisking to incorporate completely. Bring the mixture to a gentle simmer where small bubbles just begin to break the surface. The sauce should coat the back of a spoon. Season thoughtfully with salt and freshly ground black pepper, remembering the cheeses will add saltiness.
- Add the cheeses:
- Reduce heat to low and gradually add the grated Gruyère and half the Parmesan, stirring constantly in a figure-eight motion to ensure even melting and prevent the cheese from clumping or separating. Continue stirring until the sauce is completely smooth and silky with no visible cheese pieces.
- Combine with Brussels sprouts:
- Gently fold the blanched Brussels sprouts into the cheese sauce, making sure each piece is thoroughly coated. The sauce should cling to the vegetables but still be fluid enough to settle into the baking dish. Transfer this mixture to your prepared baking dish, spreading it into an even layer.
- Create the crispy topping:
- In a separate bowl, thoroughly combine the fresh breadcrumbs with melted butter and remaining Parmesan cheese, working the butter through with your fingertips until the mixture resembles wet sand. This ensures even browning. Sprinkle this mixture evenly over the Brussels sprouts, covering the entire surface for maximum crispiness.
- Bake to golden perfection:
- Place the baking dish in the preheated oven and bake for 20-25 minutes until the top is deeply golden brown and the edges are bubbling vigorously. For extra browning, place under the broiler for the final 1-2 minutes, watching carefully to prevent burning.
- Rest before serving:
- Allow the gratin to rest for 5 full minutes after removing from the oven. This crucial step lets the sauce set slightly and flavors meld. Just before serving, sprinkle with freshly chopped parsley for a bright finish.
Pin The nutmeg in this recipe is my secret weapon. I discovered its magic in creamy vegetable dishes during culinary school, and now I never make a gratin without it. Just that tiny amount transforms the sauce, adding a warmth that most people can't identify but everyone appreciates.
Make-Ahead Magic
This gratin is perfect for entertaining because you can prepare it in stages. Blanch the Brussels sprouts and make the cheese sauce up to two days ahead, storing them separately in the refrigerator. On serving day, bring both components to room temperature, combine them, add the topping, and bake. The final result will be just as delicious as if you made it all at once.
Smart Substitutions
For a lighter version substitute half and half for the heavy cream without sacrificing too much richness. The sauce will be slightly thinner but still delicious.
For gluten free needs replace traditional breadcrumbs with gluten free panko or crushed rice cereal mixed with extra Parmesan.
For a dairy free adaptation use plant based butter unsweetened oat milk and your favorite melting vegan cheese alternative. The texture will differ slightly but the flavor profile remains satisfying.
Serving Suggestions
This gratin pairs beautifully with roasted meats especially beef tenderloin or a holiday turkey where the creamy sauce complements the protein.
For an elegant vegetarian meal serve alongside wild rice pilaf and a simple green salad with vinaigrette.
During cooler months I love serving individual portions in ramekins alongside a hearty soup for a comforting dinner that feels special.
Seasonal Adaptations
Fall harvest version add diced apple and chopped walnuts to the Brussels sprouts for seasonal sweetness and crunch.
Winter holiday upgrade mix in crispy bacon bits and a pinch of cloves for a festive twist perfect for Christmas dinner.
Spring refresh incorporate lemon zest and fresh thyme into both the sauce and topping for a brighter flavor profile.
Pin This recipe is a testament to how a simple vegetable can be elevated into a showstopping side dish. Enjoy the creamy, cheesy goodness!
Recipe FAQ
- → Can I use frozen Brussels sprouts?
Yes, you can use frozen Brussels sprouts. Thaw and drain them well before cooking to avoid excess moisture in the dish.
- → What cheese substitutes work well?
Sharp cheddar or Emmental can replace Gruyère. They provide a similar melt and savory flavor profile.
- → How can I make the topping extra crispy?
Ensure breadcrumbs are well mixed with melted butter and Parmesan, then broil briefly if you prefer more crunch.
- → Is this suitable for those avoiding gluten?
Substitute regular breadcrumbs with gluten-free breadcrumbs to make this suitable for gluten-sensitive diets.
- → Can I make it ahead of time?
Assemble and refrigerate before baking. Bake just before serving for the freshest, crispiest result.
- → How do I store leftovers?
Store in an airtight container in the fridge for up to 3 days. Reheat in the oven to retain crispiness.