A recipe for roux gravy on turkey, mashed potatoes and rice includes oil, butter and flour, or fat drippings and flour. A simple formula per cup of gravy is 2 tablespoons of fat, 2 tablespoons of flour and 1 cup of a liquid such as heavy cream, milk or broth.
For a richer gravy, use heavy cream. For simpler gravies, use broth, and for a middle ground, use milk. After cooking a meat or poultry dish, pour the fat from the pan. Add butter to compensate if there is not enough fat. Add the same measure of butter as fat, and slowly mix in 1 cup of liquid per 2 tablespoons of fat or flour. Cook the mixture on the stove over low heat, and stir. Take the mixture to a simmer to get rid of lumps. For thicker gravy, continue cooking. Add desired seasonings. A bay leaf or a minced clove of garlic are examples that add flavor to gravy.
Gravy becomes thicker as it stands, so add broth or water to thin out the gravy. Unless the meat is liberally seasoned, use 1/2 teaspoon of salt per cup of liquid, but gradually introduce the salt. Taste often to ensure the gravy is not too salty.