A Cheddar or process (American) cheese is the most popular for making cheese sauce: Cheddar for a stronger flavor, process cheese for a milder taste and easy melting quality. Colby, longhorn, and Monterey Jack are also suitable. Small amounts of a hard cheese, such as Parmesan or Romano, may be added for extra tang. Mornay, a cheese sauce of European origin, is flavored with Swiss or Gruyere cheese, with Parmesan or Romano usually added.
Classic cheese sauce
Melt 2 tablespoons butter in a heavy saucepan; stir in 2 tablespoons flour, 1/4 teaspoon salt, 1/8 teaspoon pepper, and 1/2 teaspoon dry mustard (optional). Cook and stir over low heat until bubbly; do not allow it to darken. Add 1 cup milk all at once. Cook and stir until the sauce is smooth and thick. Slowly stir in 1/2 cup shredded cheese; blend until the cheese is melted and the sauce is smooth. Thin, if desired, with cream or chicken broth; heat but do not boil. Makes 1/2 cups.
Use the sauce to flavor vegetables, fish, or cooked eggs, or to make an au gratin dish: moisten cooked seafood or bite-size vegetables with a few tablespoons of sauce. Put the mixture in a well-greased, shallow baking dish. Spoon additional sauce thinly over the top; top with buttered bread crumbs. Place the dish under a preheated broiler until the sauce is bubbly and the crumbs are browned.