Pre-heat oven to 400 degrees. Lather the inside of the cavity with the juice of half a lemon. Rub a handful of salt all over the inside of the turkey. Put half of a peeled yellow onion, chopped carrots and chopped celery into the body. Close up the turkey. Rub melted butter or olive oil all over the outside of the turkey. Sprinkle salt generously all over the outside of the turkey. Place turkey breast down on the bottom rack over a sturdy roasting pan. Cook at 400 for the first 1/2 hour. I start that at around 10:30 - 11:00am. Then reduce the heat to 350 degrees for the next 2 hours. Then reduce the heat further to 225 degrees for the next two - two and a half hours. You'll know it is done when the legs swing free.