In a small saucepan, combine the apple cider, jelly and butter. Cook and stir until butter is melted. Remove from the heat and set aside. Reserve 2 tablespoons for finishing.
In a small bowl, combine minced sage and butter. With fingers, carefully loosen skin from the turkey breast; rub butter mixture under the skin. Brush turkey with apple cider. Sprinkle salt and pepper over turkey and inside cavity.
Place the apples, onion and sage leaves inside the cavity. Tuck wings under turkey; tie drumsticks together. Place breast side up on a rack in a roasting pan.
Bake, uncovered, at 325° for 3-1/2 to 4 hours or until a meat thermometer reads 180°, basting occasionally with cider mixture. Cover loosely with foil if turkey browns too quickly. Brush with reserved cider mixture. Cover and let stand for 20 minutes before slicing. Yield: 14 servings.