Simple turkey gravy from drippings using a roux, drippings, and broth.
Tilt fully cooked turkey to allow juices to run out of turkey cavity into the roasting pan. Drain drippings into a measuring cup.
Using a fat separator or a spoon, skim fat from drippings. Use your desired amount of fat for the gravy roux and discard the rest. Do not throw away the remaining juices under the fat.
In a saucepan, whisk together fat and flour together of medium low heat to make a roux. Cook for a few minutes until it has developed a light golden color.
Slowly whisk in turkey juices + however much more broth/water you need to make 4 cups of liquid.
Bring to a boil and whisk while cooking until gravy is thickened. Taste and adjust seasonings if needed. Strain if needed and serve hot.