Preheat the oven to 375°F. Grease a muffin pan or line it with muffin liners.
In a large bowl, combine the ground beef, breadcrumbs, grated Parmesan cheese, milk, ¼ cup ketchup, chopped onion, chopped bell pepper, garlic powder, dried oregano, salt, black pepper, and egg. Mix well unKl all ingredients are incorporated.
Divide the meat mixture evenly among the muffin cups, pressing gently to pack the mixture.
In a small bowl, whisk together the remaining ¼ cup ketchup, brown sugar, mustard and Worcestershire sauce for the topping.
Spoon a small amount of the topping mixture onto each meatloaf muffin.
Bake in the preheated oven for about 20-25 minutes, or unKl the meatloaf muffins are cooked through and the internal temperature reaches 160°F.
Remove from the oven and let them cool for a few minutes before serving.
