1. Preheat oven to 400º. Remove giblets from both cavities of turkey, and rinse inside and out. Loosen skin of turkey breasts, and place 2 tablespoons butter and 4 to 6 sage leaves under skin of each breast. Season turkey inside cavity and all over outside with herbes de Provence, sea salt, and pepper. Place onion, apple, celery, and remaining sage leaves in cavity of turkey and on bottom of heavy-duty roasting pan as a rack for turkey. Pour wine and apple juice in pan. Place turkey in pan.
2. Cover breast with foil, leaving legs exposed. Roast at 400º for 1 hour 30 minutes. Remove foil. Roast 1 hour more, basting every 20 minutes with pan drippings, until juices run clear when a small knife is inserted into thickest part of thigh or an instant-read thermometer registers 165º when inserted into thickest part of thigh.
3. Remove turkey from oven; baste again. Allow to rest 30 to 45 minutes before carving. Turkey will continue to cook another 5 to 10 degrees. Serve with Turkey Gravy, if desired.