Remove and discard leg truss from turkey. Pull off and discard any lumps of fat. Remove giblets and neck (they're often packed in the neck or body cavity) and save for gravy. Rinse turkey inside and out; pat dry. Rub turkey all over with butter.
Place turkey, breast up, on a V-shaped rack in a 12- by 17-inch roasting pan, or one that is at least 2 in. longer and wider than the bird. Insert a meat thermometer through thickest part of breast to the bone. (If using an instant-read thermometer, insert when checking temperature later.)
Roast in a 325° or 350° (depending on size of bird; see below) oven until thermometer registers 160°.
If turkey is unstuffed, tip slightly to drain juices from body cavity into pan. Transfer turkey to a platter. Let stand in a warm place, uncovered, for 15 to 30 minutes, then carve. If thigh joints are still pink (common in an oven-roasted bird), cut drumsticks from thighs, place thighs in a baking pan, and bake in a 450° oven until no longer pink, 10 to 15 minutes; or put on a microwave-safe plate and cook in a microwave oven at full power (100%) for 1 to 3 minutes.
Nutritional analysis per 1/4 pound boned cooked turkey with skin, based on percentages of white and dark meat in an average bird.
Oven-roasted turkey: temperatures and times
For a 10-13 lb. turkey (weight with giblets): Bake in a 350° oven for 1 1/2-2 1/4 hr.
For a 14-23 lb. turkey (weight with giblets): Bake in a 325° oven for 2-3 hr.
For a 24-27 lb. turkey (weight with giblets): Bake in a 325° oven for 3-3 3/4 hr.
For a 28-30 lb turkey (weight with giblets): Bake in a 325° oven for 3 1/2-4 1/2 hr.
Times are for unstuffed birds. A stuffed bird may cook at the same rate as an unstuffed one; however, be prepared to allow 30 to 50 minutes longer. While turkeys take about the same time to roast in regular and convection heat, a convection oven does a better job of browning the bird all over.
If using a frozen turkey, start thawing it in a pan in the refrigerator 3 to 4 days before roasting, depending on its size. During roasting, if turkey overlaps the pan rim, tuck a strip of heavy-duty foil along the sides of the pan to keep fat from dripping over.