After removing the roast turkey from oven remove drippings from bottom of the pan. Strain to remove any solid material and allow to sit 10-15 minutes for fat to rise to the surface.
Skim fat off the surface with a large spoon, reserving 4 tablespoons of the fat and one cup of the drippings.
Add turkey fat to a large saucepan and add vegetables and thyme, rosemary, and sage.
Cook over medium heat until soft, about 8 minutes.
Sprinkle flour over the mixture and stir until flour is absorbed by the liquid to form a roux.
Continue to cook while stirring an additional 2-3 minutes or until golden in color.
Add in turkey drippings while continuing to stir constantly. Cook about three minutes (continuing to stir) then add turkey stock.
Bring gravy to a simmer and reduce heat to simmer for 10-12 minutes or until thickened.
Strain gravy to remove herbs and veggies and salt and pepper to taste before serving.
You may substitute butter for turkey fat if necessary and use chicken stock instead of turkey stock.