Serves about 6
This has to be one of our favorite ways to enjoy Brussels sprouts! A unique vegetable for a gratin, it's the interesting texture of the thinly shaved sprouts that make it work. The prepped Brussels sprouts are complemented with a rich, creamy sauce and punctuated with slightly spicy, roasted walnuts.
4 tablespoons melted unsalted butter,
plus 1 tablespoon reserved for the top of the gratin
2 shallots, finely chopped
3 garlic cloves, minced
3 tablespoons all-purpose flour
2 cups heavy cream
1 teaspoon ground mustard
1/4 cup white wine
1-1/2 cup Parmesan, finely grated, plus 2 tablespoons reserved
1/4 teaspoon freshly ground black pepper
1/4 teaspoon Kosher salt
1-1/2 pounds Brussels sprouts, trimmed,
and thinly shaved with a handheld mandoline
1 cup chopped walnut pieces
1 tablespoon fresh sage, minced
1/2 teaspoon cayenne
1. Preheat the oven to 375° F. Prep the ingredients as noted above.
2. Prepare the sauce. In a large saucepan, melt the butter on low heat, then add the chopped shallot and minced garlic. Cook until the shallot is wilted and soft. Whisk in the flour. Continue whisking while cooking on low for about 1-2 minutes. This process helps removes the raw flour flavor from the roux and creates a silky, smooth sauce.
3. Remove the sauce from the heat and add the cream, ground mustard, white wine, Parmesan, pepper, and salt. Stir the ingredients together until the cheese has melted, and the sauce is smooth.
4. Add the shaved Brussels sprouts to the sauce mixture and toss to coat with the sauce. Transfer the mixture into a baking dish and top with the reserved 2 tablespoons of grated Parmesan.
5. Bake the gratin for about 40-45 minutes, or until the center is bubbly and the top a golden brown. (Check the progress at the 30-minute mark; If the top or edges are browning too quickly, tent the baker loosely with aluminum foil.)
6. Meanwhile, while the Brussels sprouts bake, toast the nuts. Melt the remaining one tablespoon of butter. In a small bowl, toss the melted butter with the walnut pieces, cayenne, and sage. Spread out the coated nuts on a baking sheet or in a dry skillet.
7. Roast the walnuts, for about 6-8 minutes, tossing occasionally, to promote even roasting and avoiding burning. Or, if using a skillet, toast the nuts, stirring frequently, until the walnuts are lightly browned. Keep a close eye on the progress of the nuts, they brown quickly!
8. Top the baked Brussels sprout gratin with the roasted nuts and serve hot.