Step 1 Remove neck and giblets from bird. Separate liver from other giblets and discard or save for another meal. (The liver, largest and softest of organ meats, clouds the broth.)
Step 2 Place remaining giblets and neck in 2-quart saucepan. Add water, onion, carrot, celery and peppercorns and bring to boil over high heat. Cover, reduce heat to low and simmer until tender, about 1 1/2 hours. Strain and reserve broth. Discard neck. Chop giblets, cover and refrigerate.
Step 3When turkey is roasted, remove from oven and transfer to platter. Lightly cover with foil and let stand about 20 minutes to allow juices to set before carving.
Step 4Meanwhile, add 1 cup reserved broth to drippings in roasting pan. Place pan over medium heat and scrape browned particles free from bottom with wooden spoon. Pour mixture into clear measuring cup and let fat rise to top. Skim fat off with spoon. Or use specially designed measuring cup that separates the fat.
Step 5To make 2 cups gravy, place 1/4 cup turkey fat in saucepan. (If necessary, add butter to make 1/4 cup.) Add enough reserved giblet broth to skimmed drippings to make 2 cups.
Step 6Heat fat over medium heat. Stir in flour and cook, stirring, until bubbly. Remove from heat. Gradually pour in dripping-stock mixture, stirring constantly with wire whisk. Return pan to heat, and cook, stirring, until gravy boils and thickens. Add whipping cream, if using, and heat through. For thinner gravy, add more broth. Stir in giblets. Season to taste with salt and pepper.