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Brussels Sprout Gratin with Gruyère

This Brussels sprout gratin transforms the humble green veggie into a show-stopping dish, layered with nutty Gruyère, creamy sauce, and a crispy golden top. It’s comfort food with a gourmet edge—perfect for family dinners, holiday feasts, or anytime you want vegetables to steal the spotlight.
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Course Main Course
Cuisine American

Ingredients
  

  • 1 ½ pounds Brussels sprouts trimmed and halved
  • Substitute: Broccoli florets or cauliflower for a similar gratin.
  • 2 tablespoons unsalted butter
  • 2 tablespoons all-purpose flour
  • Gluten-free option: Use rice flour or a 1:1 gluten-free blend.
  • 1 ½ cups whole milk warm
  • Alternative: Half-and-half for a richer sauce or oat milk for dairy-light.
  • ½ cup heavy cream
  • 1 teaspoon Dijon mustard
  • ½ teaspoon salt or to taste
  • ¼ teaspoon freshly ground black pepper
  • ¼ teaspoon ground nutmeg optional, but classic with Gruyère
  • 1 ½ cups shredded Gruyère cheese
  • Substitute: Swiss cheese Fontina, or sharp white cheddar.
  • ½ cup grated Parmesan cheese for extra depth
  • ½ cup breadcrumbs optional, for a crunchy topping

Instructions
 

  • Prep the Brussels Sprouts
  • Bring a large pot of salted water to a boil.
  • Add halved Brussels sprouts and blanch for 3–4 minutes, until bright green and just tender.
  • Drain and immediately rinse under cold water to stop cooking. Pat dry.
  • Tip: This keeps them vibrant and prevents sogginess in the gratin.
  • Make the Cheese Sauce
  • In a medium saucepan, melt the butter over medium heat.
  • Whisk in flour and cook for 1 minute, until slightly golden and nutty (this is your roux).
  • Slowly pour in warm milk while whisking to avoid lumps. Add cream.
  • Stir in Dijon mustard, salt, pepper, and nutmeg.
  • Cook for 4–5 minutes, until the sauce thickens and coats the back of a spoon.
  • Add the Cheese
  • Remove sauce from heat. Stir in 1 cup Gruyère and ¼ cup Parmesan, mixing until melted and smooth.
  • Reserve the remaining cheese for topping.
  • Cue: The sauce should be silky, creamy, and fragrant with melted cheese.
  • Assemble the Gratin
  • Preheat oven to 400°F (200°C).
  • Spread the Brussels sprouts evenly in a greased baking dish.
  • Pour cheese sauce over sprouts, making sure they’re coated.
  • Sprinkle the remaining Gruyère and Parmesan on top.
  • If using breadcrumbs, mix them with a teaspoon of olive oil or melted butter, then scatter over the surface.
  • Bake to Perfection
  • Bake uncovered for 20–25 minutes, until the top is golden brown and bubbling.
  • For an extra-crispy crust, broil for 1–2 minutes at the end (watch closely!).
  • Serve & Enjoy
  • Let the gratin rest for 5 minutes before serving so the sauce sets slightly.
  • Garnish with a sprinkle of fresh thyme or parsley for color and freshness.
Keyword Brussels Sprout Gratin with Gruyère
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