Roux refers to a mixture of flour and fat used to thicken sauces, soups, and stews. Though usually made with butter, Rouxs are also made with bacon or poultry fats, margarine, and vegetable oil. The mixture is cooked for a brief time to remove the raw taste of the starch from the flour. Longer cooking results in a darker color, which is favorable in Creole cooking where Rouxs are cooked for long periods until they reach a dark brown color.