Preheat oven to 375°F. Grease a 24-cup mini muffin tin.

In a large bowl, mix together beef, pork, breadcrumbs, Parmesan, onion, milk, egg, garlic, Worcestershire sauce, salt, and pepper until just combined.

Take about 2 tbsp of meat mixture and flatten into a thin patty in your palm. Place 1 tsp of mozzarella in the center. Shape meat around cheese into a ball.

Place in prepared muffin cup. Repeat with remaining meat and cheese.

In a small bowl, stir together ketchup and brown sugar. Brush topping onto each meatloaf bite.

Bake for 20-25 minutes until meat is cooked through and cheese is melted.

Allow to cool slightly before removing from tin. Serve warm.