The daughter sauces of the classic French mother sauce, Béchamel, include Mornay sauce, Nantua sauce, and Mustard sauce.  Mornay sauce is a creamy white cheese sauce with grated Parmesan and Gruyère cheese melted into it.  Nantua Sauce is made with a combination of béchamel and crayfish butter or bisque.  Mustard Sauce uses either Dijon or English mustard mixed with béchamel.  There are numerous other daughter sauces derived from béchamels, such as Cheddar cheese sauce, Demi-Glace Sauce, and Hollandaise Sauce, which combines melted butter with egg yolks, lemon juice, and seasonings.