In a large skillet, cook ground beef and onion over medium heat until beef is no longer pink. Add garlic powder, onion powder, Worcestershire sauce, and pepper. Cook for 5 minutes more, stirring occasionally.
In a large bowl, combine ground beef mixture, cheddar cheese, mozzarella cheese, and crushed crackers. Spoon mixture into cupcake liners, filling each about 3/4 full.
Top each cupcake with a dollop of ketchup. Bake in preheated oven for 25 minutes or until cupcakes are cooked through.
Interesting Facts
These cupcakes are a great way to use up leftover ground beef.