How to Make It
Preheat the oven to 375°. Set the turkey on a rack in a roasting pan and pat dry. Loosely fill the cavity with 5 cups of the Wild Mushroom Stuffing and the neck cavity with 1 cup of stuffing. Rub the skin with 2 tablespoons of the butter and season generously with salt and pepper. Loosely tie the legs together with kitchen string. Add 2 cups of water to the pan.
Roast the turkey in the center of the oven until the skin begins to brown, about 45 minutes. Loosely cover the turkey with a large sheet of foil. Lower the oven temperature to 325° and roast the turkey for about 4 1/2 hours longer, until an instant-read thermometer inserted in the inner thigh registers 165°. Add water to the pan throughout roasting as necessary to keep the pan moistened. Transfer the turkey to a platter, cover loosely with foil and let rest for at least 30 minutes.
Meanwhile, in a medium saucepan, simmer the heart and gizzard in the Turkey Stock over moderately low heat until tender and the stock is reduced to 4 cups, about 45 minutes. Strain the reduced stock into a heatproof bowl. Finely chop the heart and gizzard.
In a small skillet, melt 1 teaspoon of the butter. Add the turkey liver and cook over moderately high heat, turning once, until lightly browned outside and light pink within, about 4 minutes. Transfer the turkey liver to a plate and let cool, then finely chop and add it to the heart and gizzard.
In a small skillet, melt the remaining 4 tablespoons of butter. Add the flour and whisk over moderate heat until the roux is the color of peanut butter and has a nutty aroma, about 8 minutes. Scrape the roux into a bowl.
Set a fine strainer over a medium bowl. Pour the drippings from the roasting pan (there should be about 1 cup of juices) into the strainer and spoon off the fat. Set the roasting pan over 2 burners. Add the reduced turkey stock and simmer over moderately high heat, scraping up any browned bits from the bottom and side of the pan. Strain the stock into a medium saucepan and add the reserved pan juices from the bowl. Whisk in the roux and bring to a boil. Simmer the gravy over moderate heat until thickened, about 7 minutes. Stir in the reserved giblets and season with salt and pepper.
Spoon the stuffing from the turkey into a bowl. Carve the turkey and serve with the stuffing and gravy.