Combine soup, mayonnaise, garlic and black pepper in a bowl; mix well. Stir in cheddar cheese.
Place frozen vegetables in a baking dish. Spoon soup mixture over vegetables. Mix to coat vegetables evenly.
Bake 35-40 minutes or until hot. Remove from oven. Sprinkle fried onions over vegetable mixture. Return to oven 5 minutes or until onions are golden. Serve immediately.