1 1/2 cups 1% cottage cheese
1 1/2 cups skim milk or  buttermilk
1 teaspoon dried mustard or 1 tablespoon prepared mustard
 pinch of {cayenne}
1/4 teaspoon nutmeg
1/2 teaspoon salt
1/4 teaspoon ground black pepper
1/4 cup grated onions
1 cup grated extra-sharp cheddar cheese (4 ounces)
1/2 pound uncooked elbow macaroni
2 tablespoons finely grated Pecorino Romano or  Parmesan cheese
1/4 cup bread crumbs

Preheat the oven to 375 degrees. Prepare a 9- or 10-inch square baking pan with a light coating of cooking spray or oil.

In a blender, combine the cottage cheese, skim milk or buttermilk, mustard, cayenne, nutmeg, salt, and pepper and purée until smooth. In a large bowl, combine the puréed mixture with the onions, cheddar cheese, and uncooked macaroni. Stir well. Pour the macaroni and cheese mixture into the baking pan. Combine the grated Pecorino or Parmesan cheese and the bread crumbs and sprinkle over the top.

Bake for about 45 minutes, until the topping is browned and the center is firm.