Stir the soup, 1 cup cheese, sour cream, black pepper, vegetables and 1 can onions in a 3-quart shallow baking dish.
Bake at 400 degrees F for 20 minutes or until the vegetable mixture is hot and bubbling. Stir the vegetable mixture. Sprinkle with the cheese and remaining onions.
Bake for 5 minutes or until the onions are golden brown.