The foundation for a large proportion of sauces is in what the French cook knows as a roux, and we as "drawn butter." As our drawn butter is often lumpy, or with the taste of the raw flour, I give the French method as a security against such disaster.
Melt butter in a saucepan, and add flour; one ounce of butter to two of flour being a safe rule. Stir till smooth, and pour milk in slowly.
With milk it is called cream roux, and is used for boiled fish and poultry.
Where the butter and flour are allowed to brown, it is called a brown roux, and is thinned with the soup or stew which it is designed to thicken.
Capers added to a white roux—which is the butter and flour, with water added—give caper sauce, for use with boiled mutton. Pickled nasturtiums are a good substitute for capers.
Two hard-boiled eggs cut fine give egg sauce.
Chopped parsley or pickle, and the variety of catchups and sauces, make an endless variety; the white roux being the basis for all of them.