Basic Roux The fat used in roux may be butter, shortening, lard, oil, or even bacon drippings. Combine fat with an equal amount of flour; 1/2 cup of each will make a good amount and any excess can be stored in the refrigerator. (Many cookbooks call for a little more fat than flour - 2/3 cup oil to 1/2 cup flour is a common ratio.) Melt the fat in a black skillet over low heat. When warm and fluid, sprinkle the flour in a little at a time, stirring. Stir constantly until brown (this may take 20 to 30 minutes); immediately remove from heat or add ingredients your recipe calls for. If it burns even slightly, throw it out and start over again. Source: Rattray, Diana. "Recipes for gumbo, along with a basic roux." About.com. February 7, 2009 .