Preheat oven to 350 degrees F. Spray a muffin tin with nonstick cooking spray; set aside.
In a large mixing bowl, combine ground beef, onion, eggs, bread crumbs, 1/4 cup ketchup, Parmesan, garlic powder, oregano, salt and pepper.
Divide meat mixture evenly between 12 muffin cups and press down to fill the cup. In a small mixing bowl, combine cup ketchup and Worcestershire sauce and divide evenly between muffin cups, spreading evenly on top.
Bake for 20-25 minutes until lightly browned on the edges.