1. Adjust the oven racks so the covered roasting pan fit easily inside. Preheat the oven to 260°C.
2. Rub the butter on the outside and in the cavity of the turkey. Sprinkle the salt and pepper on the inside and the outside of the turkey. Put the celery, onion and carrot in the cavity. Place the turkey, breast-side up, in a large roasting pan. Pour the boiling water into the pan. Cover with a tight-fitting lid and put the pan in the oven.
3. Start a timer when the oven temperature returns to 260°C. Bake for exactly 1 hour and turn off the oven. Do not open the oven door! Leave the turkey in the oven until the oven completely cools; this may take 4 to 6 hours. Reserve the pan juices and refrigerate the turkey if it will not be served soon after roasting.
Recipe adapted from Georgia Cooking in an Oklahoma Kitchen by Trisha Yearwood (c) Clarkson Potter 2008