Heat oven to 450. Slice the tops off the onions and peel them, leave the roots on. Cut each onion into 8 wedges taking care to keep wedges intact. Place onions in single layer in 9x13 pan. Toss gently with oil then replace back into single layer. Pour vinegar over top and sprinkle with salt and seasoning. Cover with foil and bake 45 min then uncover and bake 5- 10 minute.