bacon is sometimes rendered to produce fat to use in the roux. If clarified butter is not available, vegetable oil is often used when producing dark roux, since it does not burn at high temperatures, as whole butter would.

Instead of butter, in Cajun cuisine roux is made with lard, oil, or drippings from meat, poultry, or bacon. It is often cooked to a medium or dark brown color, which lends considerable richness of flavor while