The Golden Formula: (for 8 cups of gravy) 1/2 cup fat Use the oil that separates from your turkey drippings. If you don't have enough, add butter. 1/2 cup flour Cook the flour with the fat to make a roux for thickening the gravy. For a darker gravy, cook the roux longer. (Note: Darker roux has less thickening power.) 8 cups broth Upgrade store-bought broth by simmering it with a sliced onion, a bay leaf, a few sprigs of thyme, parsley and/or sage, and the turkey giblets for about 2 hours. Quick Fixes: Too Thick? Add a splash of water, broth, brandy or bourbon. Too Thin? Mix equal parts flour and soft butter; whisk into boiling gravy. Too Lumpy? Strain the gravy through a fine-mesh sieve.