Roux

Roux is a mixture of flour and fat cooked together and used to thicken sauces, typically made from equal parts flour and fat by weight. The flour is stirred into melted fat or oil on the stovetop until smooth and cooked to the desired level of brownness, giving a white, blond or brown roux depending on how far it is cooked, with butter, bacon drippings and lard among the common fats used. Roux serves as the thickening base for gravy, sauces, soups and stews, with a dish other ingredients added once the roux itself is complete. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/