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A person lifting up a spoonful of baked Brussels sprouts in a cream sauce out of an oval baking dish.

Brussels Sprouts Gratin

Course: Side Dish
Cuisine: American
Keyword: best Brussels sprouts recipe, how to make Brussels sprouts gratin, Thanksgiving side dish recipe
Prep Time: 15 minutes
Cook Time: 40 minutes
Total Time: 55 minutes
Servings: 4
Calories: 468kcal
Brussels Sprouts Gratin is always such a big hit, especially for that special holiday feast. Even non-veggie-loving people love this dish. Roasting the sprouts deepens the flavor and softens them. The smoked Gruyere with the pancetta and cream sauce puts it over the top.
Print Recipe

Equipment

  • 2 quart baking dish

Ingredients

  • 1 lb Brussels sprouts rinsed and patted dry
  • 2 tbsp olive oil
  • tsp Kosher salt divided
  • tsp black pepper freshly ground, divided
  • 4 oz pancetta cubed
  • ½ cup onion chopped
  • 3 cloves garlic minced
  • 1 tbsp all-purpose flour
  • cup heavy cream plus a little extra
  • ½ cup smoked Gruyere shredded
  • ¼ tsp nutmeg ground
  • ¾ cup Panko bread crumbs
  • 3 tbsp unsalted butter melted

Instructions

  • Preheat oven to 400°F.
  • Place the Brussels sprouts in a large bowl and toss them with the olive oil and a couple of pinches each of salt and pepper (about ½ tsp each of salt and pepper. Spread the sprouts onto a baking sheet and roast for 20 minutes, flipping them over halfway through.
  • Remove the sprouts from the oven, and when cool enough to handle, roughly chop them. (See NOTES).
  • Meanwhile, cook the pancetta in a large skillet over medium-high heat until crisp. Use a slotted spoon to remove the pancetta from the pan. Place in a bowl and set aside.
  • Leave the rendered grease in the pan. Add the onions and cook until soft and starting to brown, about 5 minutes. Add the garlic and cook for another 30 seconds.
  • Stir in the flour to create a roux and cook for about 1 minute.
  • Carefully pour in the heavy cream and stir until slightly thickened, about 2 minutes. Add the cheese and stir until melted. Season with ½ tsp of salt and pepper. Stir in the nutmeg and reserved pancetta. If the sauce is too thick, thin with more cream until the right consistency. It should be the consistency of thick gravy.
  • Place the chopped sprouts in a 2-quart baking dish. Pour the cream sauce over the top of the sprouts.
  • In a bowl, mix together the breadcrumbs with the melted butter. Sprinkle the breadcrumb mixture over the top of the cheese sauce.
  • Bake for 20 minutes until bubbly and golden on top.

Notes

See the video near the top of the blog post for visual guidance.  If you like the video, please subscribe to our YouTube channel.
If you want the sprouts to be nice a chunky, simply halve them, rather than quartering them or chopping them.  Depending on the size of the sprouts, if you leave them in larger pieces, they may need to bake longer to become nice and soft.  After 20 minutes, pierce one with a knife.  If there is much resistance, cook for another 10 minutes or so.  You'll probably need to cover the dish with foil at this point to prevent the bread crumbs from browning too much.
We love using smoked Gruyere, but other great cheese choices include white cheddar, Fontina, or regular Gruyere (not smoked). 
To make the dish vegetarian, simply omit the pancetta and use two tablespoons of butter or olive oil to saute the onions and make the roux.  If you omit the pancetta, you'll want to increase the salt amount to ¾ tsp for the sauce. 
This recipe easily feeds 4 people.  Double the recipe to serve 8 or more and bake in a 9x13-inch dish. 
The dish can be made up to 1 day in advance, prior to baking.  Cover and keep in the fridge.  Take it out of the fridge a couple of hours before baking to allow it to come to room temp. Add the bread crumb mixture and bake as directed. 

Nutrition

Calories: 468kcal | Carbohydrates: 24g | Protein: 10g | Fat: 32g | Saturated Fat: 12g | Polyunsaturated Fat: 2g | Monounsaturated Fat: 8g | Trans Fat: 1g | Cholesterol: 96mg | Sodium: 1188mg | Potassium: 602mg | Fiber: 5g | Sugar: 4g | Vitamin A: 1716IU | Vitamin C: 99mg | Calcium: 111mg | Iron: 3mg