Ina Garten from the Food Network offers a recipe for cauliflower gratin, a type of scalloped cauliflower casserole. To make this recipe, first preheat the oven to 375 degrees Fahrenheit.
Cut 1 3-pound cauliflower head into large florets. Boil a large pot of water, and salt it with kosher salt. Add the cauliflower florets, and cook them until firm but slightly tender, approximately five to six minutes. Drain the cauliflower, and set it aside.
Add 2 tablespoons of unsalted butter to a medium saucepan, and melt it over low heat. Add 3 tablespoons of all-purpose flower, and cook the ingredients for two minutes, stirring constantly. Heat 2 cups of milk, and add it to the butter and flour. Continue to stir the mixture until it boils. Whisk the ingredients until thickened, approximately one minute.
Remove the ingredients from the heat, and add 1 teaspoon of salt, 1/2 teaspoon of freshly ground black pepper, 1/4 teaspoon of grated nutmeg, 1/2 cup of freshly grated Gruyère cheese and 1/2 cup of freshly grated Parmesan.
Pour a third of the sauce into an 8-inch-by-11-inch casserole dish. Layer the cauliflower on top, and then pour the remaining sauce over it. Combine 1/4 cup of fresh bread crumbs with 1/4 cup of freshly grated Gruyère cheese, and sprinkle the mixture over the casserole. Melt 2 tablespoons of unsalted butter, and drizzle it over the bread crumbs. Top the gratin with salt and pepper, and then bake it until the top browns, approximately 25 to 30 minutes.