Brussels Sprouts in Sherry Cream Sauce

4 tablespoons (½ stick) unsalted butter
4 garlic cloves, minced
1 pound Brussels sprouts, bottom stems trimmed, cut crosswise into ½-inch slices
2 tablespoons all-purpose flour
¼ cup dry sherry, such as Manzanilla
1 cup heavy cream
½ cup freshly grated Parmesan cheese
½ teaspoon salt
1/8 teaspoon freshly ground black pepper
A few gratings of fresh nutmeg

Try to buy the firmest, smallest sprouts, as they have the most delicate nutty flavor.

Preheat the oven to 350°F. In a large skillet, melt 2 tablespoons of the butter over medium heat. Add half of the garlic and stir until fragrant, about 1 minute. Add half of the Brussels sprouts. Cook, stirring occasionally, until heated through, about 2 minutes. Tossing the sprouts, sprinkle with 1 tablespoon of the flour, and stir for 1 minute without letting the flour brown. Stir in 2 tablespoons of the sherry, then ½ cup of the heavy cream. Bring to a simmer. Cook, stirring often, until the sauce thickens and the Brussels sprouts are just tender, about 3 minutes. Transfer to a large bowl. Repeat the procedure with the remaining butter, garlic, Brussels sprouts, flour, and cream. Stir in ¼ cup of the cheese. Season with the salt, pepper, and nutmeg. Spread in a buttered 9 × 13-inch baking dish. Sprinkle with the remaining ¼ cup cheese. (The Brussels sprouts can be prepared up to 1 day ahead, cooled, covered, and refrigerated.)
Bake until the sauce is bubbling, about 25 minutes. Serve hot.