Transfer ½ cup of the turkey or chicken stock to a freezer-safe container and freeze for reheating the gravy later.

Preheat the oven to 400F. Pat the turkey pieces dry all over with paper towels, and arrange on a rimmed baking sheet. Season lightly all over with salt and pepper. Roast until browned, fragrant, and cooked through, about 30-40 minutes. (The internal temperature should be around 165F.)

Transfer the roasted turkey to a large saucepan or pot along with all drippings and brown bits from the baking sheet. Add the remaining 7 + 1/2 cups stock, white wine, thyme, and bay leaves and bring to a simmer. Simmer for 30 minutes without stirring, and skim any scum that appears on the surface and discard. Remove the turkey with tongs and strain the liquid into a heat-safe bowl and keep warm.

In a separate saucepan or pot, melt the butter over medium heat. Whisk in the flour a little at a time and continue mixing until the mixture is smooth and slightly golden in color. Ladle the warm broth into the roux 1-2 cups at a time while whisking continuously and bring to a simmer. Continue to cook, still whisking, until the gravy has thickened slightly, about 5 minutes more. Taste and season with more salt and pepper if needed.

Let the gravy cool, then transfer it to a freezer-safe container for up to a month!

To reheat, add the frozen gravy to a saucepan with the reserved frozen ½ cup of stock over low heat and cover. Whisk frequently as the gravy heats to keep lumps from forming, and keep heat low to keep gravy from scorching.