Thaw the turkey completely in the refrigerator (allow 1 to 4 days, depending on size).
Preheat oven to 325°F (165°C).
Remove giblets and neck from the turkey cavity.
Pat the turkey dry with paper towels.
Season inside the cavity with salt and pepper; add aromatics if desired (lemon, onion, garlic, herbs).
Tie the legs together with kitchen twine.
Tuck wing tips under the back.
Rub the skin with butter or oil; season with salt and pepper (and herbs/spices if desired).
Place turkey breast-side up on a rack in a roasting pan.
Insert an oven-safe meat thermometer into the thickest part of the breast (avoid bone).
Roast uncovered, then loosely tent with foil if the skin browns too quickly.
Baste every 30 to 60 minutes if desired (optional).
Roast until the turkey reaches:
165°F (74°C) in the thickest part of the breast
175°F (79°C) in the thickest part of the thigh (if you want extra assurance)
Estimated timing (start checking early; ovens vary):
12–15 lb: about 2.5–3.5 hours
15–18 lb: about 3–4 hours
18–22 lb: about 3.5–4.5 hours
22–24 lb: about 4.5–5.5 hours
Remove from oven when target temperatures are reached.
Tent loosely with foil and rest 15–30 minutes before carving.
Carve and serve.