In a small bowl, combine the butter, lemon juice, lemon peel and minced thyme. Pat turkey dry. Sprinkle salt and pepper over skin of turkey and inside cavity; brush with butter mixture. Place the lemon, onion, garlic and thyme sprigs inside cavity. Skewer turkey openings; tie drumsticks together.
Place flour in oven bag and shake to coat. Place the bag in a roasting pan; add turkey, breast side up. Cut six 1/2-in. slits in top of bag; close bag with tie provided.
Bake at 350° for 2-1/4 to 2-3/4 hours or until a meat thermometer reads 180°. Remove turkey to a serving platter and keep warm. Let stand for 15 minutes before carving. If desired, thicken pan drippings for gravy. Yield: 14-16 servings.