Preheat oven to 350 degrees Fahrenheit. Spray pan with non stick cooking spray. Heat milk, water and butter to boiling; stir in contents of both pouches of potatoes; let stand one minute. Stir in corn. Spoon half the potato mixture in pan. Sprinkle half each of cheese and onions; top with remaining potatoes. Sprinkle with remaining cheese and onions. Bake 10 to 15 minutes until cheese is melted. Enjoy !