Preparation

• 位置在烤箱的中心架和热the oven to 375°F. In a food processor fitted with the slicing blade, slice the Brussels sprouts and shallots.
• In a 12-inch oven-safe skillet, melt the butter over medium heat. Continue to cook the butter until it begins to brown and smell nutty. Set aside 1 Tbs. of the browned butter in a medium bowl.
• Add the Brussels sprouts, shallots, 2 tsp. salt, and 1/2 tsp. pepper to the pan and toss to combine. Cook, stirring occasionally, until the Brussels sprouts and shallots begin to soften and brown in spots, about 6 minutes. Remove the pan from the heat.
• Meanwhile, in a 2-quart saucepan over medium heat, combine the cream, Gruyère, nutmeg, cayenne, and 1/4 tsp. salt. Heat until the cheese is melted, whisking occasionally, about 4 minutes. Do not boil. Add the sauce to the Brussels sprouts, carefully stirring to combine.
• Add the panko, Parmigiano, rosemary, and a pinch of salt to the reserved butter and mix thoroughly. Top the sprout mixture with the panko mixture.
• Bake until the crumbs are browned and the Brussels sprouts are tender, 10 to 15 minutes. Let cool for about 5 minutes before serving.

For a more formal presentation, transfer the Brussels sprout mixture to a 12-inch-wide, 1-1/2-inch-deep ceramic baking dish before topping with the panko and baking.