You can enrich the stock for this gravy with any odd poultry parts that you may have in your freezer. Make the stock while the turkey roasts in its foil wrapper, then finish the gravy with the turkey drippings while the bird continues to roast unwrapped.

Turkey giblets (including neck) and wing tips from a
   12–14-lb. turkey, rinsed
5 shiitake mushrooms, trimmed and coarsely chopped
2 ribs celery, coarsely chopped
2 medium yellow onions, peeled and coarsely chopped
2 medium carrots, peeled, trimmed, and coarsely chopped
2 cloves garlic, crushed and peeled
5 sprigs of one fresh herb or a mixture, such as thyme,
   oregano, savory, tarragon, and basil
1 bay leaf
1⁄2 cup white wine or dry vermouth
6 tbsp. turkey fat skimmed from reserved turkey drippings
6 tbsp. flour
2 cups reserved turkey drippings, skimmed of fat, or
   enough turkey drippings with the addition of chicken
   stock or water to yield 2 cups
Salt and freshly ground black pepper

1. Put giblets, wing tips, mushrooms, celery, onions, carrots, garlic, herbs, bay leaf, wine, and 5 1/2 cups water into a medium pot. Bring to a boil over high heat, skimming any foam that rises to the surface. Reduce heat to medium and gently boil until stock has reduced to about 2 cups, 1–1 1/2 hours. Strain stock into a bowl, setting neck aside, and discard solids. Pick meat off neck bone, add to stock, and discard bones. Skim off any fat from stock and set stock aside.

2. Heat turkey fat in a medium saucepan over medium heat. Add flour and cook, stirring constantly, for 4–5 minutes. Gradually whisk in stock and neck meat, then the turkey drippings, and simmer, stirring often, until gravy thickens, 10–15 minutes. Season to taste with salt and pepper. Serve warm in a gravy boat, if you like.