Perfect Roast  with Best-Ever Gravy
1 18-pound fresh turkey
About 12 cups of your favorite stuffing
8 tbsp unsalted butter, at room temperature (1 stick)
Salt and freshly milled black pepper
2 1/2 quarts Homemade Turkey Stock, or more as needed
unsalted butter, melted as needed
3/4 cup all-purpose flour
OPTIONAL: 1/3 cup port, dry sherry, or bourbon

 Position a rack in the lowest position of the oven and preheat to 325° F.
 Reserve the turkey neck and giblets to use in gravy or stock. Rinse the turkey inside and out with cold water. Pat the turkey skin dry. Turn the turkey on its breast.
 Loosely fill the neck cavity with stuffing.
Using a thin wooden or metal skewer, pin the neck skin to the back. Fold the turkey's wings behind the back or tie to the body with kitchen string.
Loosely fill the large body cavity with stuffing. Place any remaining stuffing in a lightly buttered casserole, cover and refrigerate to bake as a side dish.
 Tie together drumsticks with kitchen string.
 Place the turkey, breast side up, on  rack in roasting pan. Rub all over with the softened butter.
Season with salt and pepper.
Tightly cover the breast area with aluminum foil.
Pour 2 cups of the turkey stock into the bottom of the pan.
 Roast the turkey, basting all over every 30 mins with the juices on the bottom of the pan (lift up the foil to reach the breast area), until a meat thermometer inserted in  meaty part of the thigh (but not touching a bone) reads 180°F and  stuffing is at least 160°F, about 4 ¼ hours. Whenever  drippings evaporate, add stock to moisten them, about 1 ½ cups. Remove the foil during  last hour to allow  breast skin to brown.
 Transfer turkey to large serving platter and let it stand for  20 mins before carving. Increase the oven temperature to 350°F. Drizzle ½ cup turkey stock over stuffing in  casserole, cover, and bake until heated through, about 30 mins.
 Meanwhile, pour  drippings from roasting pan into  heatproof glass bowl or large measuring cup. Let stand for 5 mins, then skim off and reserve clear yellow fat that has risen to top. Measure ¾ cup fat, adding melted butter if needed. Add enough turkey stock to  skimmed drippings to make 8 cups total.
 Place roasting pan in two stove burners over low heat and add  turkey fat. Whisk in  flour, scraping up browned bits on the bottom of the pan, and cook until lightly browned, about 2 mins. Whisk in  turkey stock and  optional bourbon. Cook, whisking often, until gravy has thickened and no trace of raw flour taste remains, about 5 mins. Transfer the gravy to  warmed gravy boat. Carve the turkey and serve the gravy and the stuffing alongside. Makes about 18 servings, with about 7 cups gravy.