Preheat the oven to 350°F. Spray a muffin pan with nonstick cooking spray.
In a large bowl, combine the ground beef, egg, milk, breadcrumbs, garlic powder, onion powder, salt and pepper. Mix together thoroughly.
Divide the ground beef into 12 muffin cups. Press into the bottom and a little up the sides.Add the toppings (1.) 1 tsp onion, (2.) 1 tsp frozen peas, (3.) 1 tsp mozzarrella, (4.) ketchup.
Bake for 30-35 minutes, or until beef is cooked and no longer pink. Cheese will slightly brown on edges. Let cool for 5 minutes, then use a small spatula to help loosen the meatloaf muffins from the pan. Serve and enjoy!