A roux is a mixture of flour and fat, usually butter or margarine, that is cooked for use as a thickener for gravies and sauces. There are three types of roux: white, blond and brown. Their color is determined by the length of time they are cooked. The white roux, which is cooked for 1 or 2 minutes until the raw flour taste has dissipated, is used to thicken delicately flavored sauces. Blond roux is cooked a few minutes longer than white roux until it is golden brown in color and has a pleasantly mild flavor. Blond roux is used in lightly colored sauces and gravies. A brown roux is generally a combination of beef or pork drippings, or oil, and flour, which is slowly cooked to a rich brown color. It has a nutty aroma and flavor. It is used to flavor and thicken rich dark soups and sauces. Cajun and Creole dishes are often flavored with brown roux.