Pour 1 cup of the stock into a large roasting pan and set the turkey in the pan. Add the butter to the pan and roast the turkey for 30 minutes. Baste with the pan juices. Reduce the oven temperature to 350° and roast for 45 minutes. Add the apple cider to the pan, baste the turkey and roast for about 1 hour and 15 minutes, or until the skin is richly browned; if the skin on the legs browns too quickly, cover them with foil. Baste again and cover the whole bird with foil. Roast the turkey for about 1 hour and 20 minutes longer, or until an instant-read thermometer inserted in an inner thigh registers 170° and the stuffing registers 165°. Transfer the turkey to a carving board and cover the bird loosely with foil.