Make Brine; set aside.
Make an incision in the skin of the turkey at the hip, where the leg attaches to the body. Separate the bone away from the backbone by pushing the leg back to dislocate it from the hip. Run the knife through the joint disconnecting it from the body. Make a cut to remove the backbone leaving only the "shell" of the turkey intact. Reserve backbone. Remove wings and reserve. Add the turkey" shell" to the brine. Cover and refrigerate for 2 days, turning occasionally. Chill gizzard and heart separately to reserve for Pan Gravy. Reserve legs for the Braised Turkey Leg Recipe.
Remove turkey shell from brine about 1 hour before roasting. Pat turkey shell dry with paper towels and sprinkle with salt and pepper.
Preheat oven to 350° F. Place the turkey shell on a rack in a roasting pan with the tips of the breast down. Insert meat thermometer into thickest portion of the breast. Roast 1 hour. Spoon juices over turkey, if any. Continue to roast about 1 hour 15 to 1 hour 45 minutes more or until internal temperature reaches 170°F, spooning juices over turkey every 30 minutes. Cover with foil and let stand 20 minutes.
Serve with Braised Turkey Legs and Pan Gravy.
In a very large bowl combine kosher salt, sugar, thyme, bay leaves, and peppercorns. Add hot water; stir until salt and sugar are dissolved. Add 2 quarts ice; let stand until ice melts.