In large pan put soup, water, and garlic; bring to a boil over high heat. Stir in macaroni, green onion, oregano, and pepperoni; cook for 6 to 8 minutes or until macaroni is almost done.
Pour soup into 4 oven-proof bowls. Top each with 1⁄4 cup mozzarella cheese, 1⁄4 cup cheddar cheese, and some oregano. Broil for 3 to 5 minutes or until cheese is bubbly and lightly browned.
Or serve soup in a small round, crusty loaf of bread. Cut top off bread and scoop out insides. Fill with soup, top with cheeses, and broil as directed above. Try different “toppings” as well, such as mushrooms, onions, and sausage.