Whisk together ¼ cup drippings (or ¼ cup melted butter, if not using drippings) and flour in a saucepan over medium heat, stirring continuously until mixture reaches a bubbly boil and forms a ball. This mixture is referred to as a roux (pronozd roo).
Whisk in broth/liquids; add bouillon if not using drippings.
Allow the gravy to cook, whisking continuously for ~5 minutes, until thickened.