FOR THE TURKEY: Preheat the oven to 350°F.
1 fresh whole turkey (about 15 pounds)
If the turkey has a metal clamp on its legs, remove it. Remove the giblets and neck from the cavity, if included, and reserve for another use or discard. Remove the cavity fat.
6 tablespoon butter (at room temperature)
Salt and pepper
6 sage leaves
In a small bowl, mash the 6 tablespoons room-temperature butter until smooth and season with salt and pepper. Using your fingers, and starting from the cavity end of the turkey, separate the skin from the breast meat, being careful not to tear the skin. Gently rub the softened butter evenly over the breast meat, then insert 6 of the sage leaves under the skin, placing 3 leaves on each breast half.
6 tablespoon butter (melted)
Freshly ground black pepper
1/2 cup dark-roasted coffee beans
Pat the skin back into place, and then brush the whole exterior of the bird with some of the melted butter. Season the turkey all over, including the cavity, with salt and pepper. Sprinkle the coffee beans inside the cavity.
1 tablespoon rendered bacon fat (melted)
1 onion (cut in half lengthwise and julienned)
Brush the bottom of a roasting pan just large enough to accommodate the turkey with the bacon fat, then make a bed of the onion slices in the center of the pan. Place the turkey, breast side up, on top of the onion.
12 sage leaves
5 garlic cloves (peeled but left whole)
5 cup chicken or turkey broth (heated)
Place the turkey in the oven and roast for 1 hour. Baste the turkey with some of the melted butter and add the garlic, the remaining 6 sage leaves, and 5 cups of the broth to the pan. Continue to roast the turkey, basting with butter at regular intervals a few more times, for another 1 1/2 to 2 hours. If the turkey is browning too much, tent with aluminum foil. The turkey is done if when a thigh joint is pierced the juices run clear, or when an instant-read thermometer inserted into the thickest part of a thigh away from bone registers 155° to 165°F.
Remove the turkey from oven, transfer to a platter, and tent with aluminum foil. Let rest for about 20 minutes.
2 to 3 cup chicken or turkey broth (heated)
1/2 Cup instant quick-dissolving flour such as Wondra
Salt and pepper
FOR THE GRAVY: Before beginning, remove any stray coffee beans that may have escaped from the turkey cavity into the roasting pan. Set the roasting pan with the onion slices and juices on the stove top over medium-high heat. You may need to straddle the pan over two burners. Using a wooden spoon, stir up any browned bits stuck to the pan bottom and continue stirring for a few minutes. Sprinkle the flour evenly over the onion and juices and stir until well combined, 1 to 2 minutes. Add 2 cups of the broth and any juices that have collected around the turkey on the platter, then simmer gently, whisking occasionally, until thickened, 8 to 10 minutes, If the gravy seems too thick, add more broth. Season with salt and pepper. Pour the gravy into a warmed gravy boat and keep warm.