Thaw: Thaw the turkey in the refrigerator, allowing 24 hours for every 4–5 pounds.
Brine: Place the turkey in a brining bag set inside a large pot or cooler. Pour the completely cooled brine over it, seal, and refrigerate for 12–24 hours.
Prep: Preheat the oven to 325°F. Remove the turkey from the brine and discard the brine. Rinse the turkey gently inside and out with cold water, then sanitize the sink. Pat it completely dry and set it breast side up in a roasting pan.
Season: Rub the skin all over with oil or butter. Sprinkle with rosemary, sage and pepper. Place the onion, fruit and herb sprigs in the cavity, if using. Tuck the wing tips under.
Roast: Roast uncovered for about 3 to 3¾ hours for a 12–14 lb turkey. When the breast is golden, tent it loosely with foil.
Check for doneness: Begin checking 30 minutes early. The turkey is done when an instant-read thermometer reads 165°F in the thickest part of the breast, the innermost thigh, and the wing.
Rest and carve: Tent the turkey with foil and rest 20–30 minutes before carving.