Pour turkey drippings into a measuring cup; skim off excess fat until you have about 1/4 cup fat (add turkey stock or water if needed to reach 2 to 3 cups total liquid).
Place drippings in a saucepan over medium heat.
Sprinkle in flour 1 tablespoon at a time, whisking constantly, until smooth and bubbling (about 2 to 4 tablespoons flour for 2 to 3 cups liquid).
Cook the roux 1 to 2 minutes, whisking, until it smells nutty and the mixture turns slightly darker.
Slowly whisk in turkey stock or hot water a little at a time until the gravy is smooth and reaches your desired thickness.
Simmer 3 to 5 minutes, whisking occasionally.
Season with salt and black pepper to taste.
Add pan drippings bits as desired; whisk to combine.
Strain if you want a smoother gravy.
Serve hot.