Sauce Béchamel is a classic white sauce made from a roux of butter and flour, combined with milk. It is one of the five mother sauces in French cuisine and serves as a base for many other sauces, such as Mornay sauce, which includes cheese. To prepare Béchamel, the butter is melted, flour is added to create a paste, and then milk is gradually whisked in until the sauce thickens. It is often seasoned with salt, pepper, and nutmeg, making it a versatile ingredient in dishes like lasagna, macaroni and cheese, and creamy soups.