Preheat your oven to 375°F (190°C). Grease a muffin tin with cooking spray.
In a large bowl, combine ground beef, breadcrumbs, milk, ketchup, chopped onion, bell pepper, carrot, egg, Worcestershire sauce, garlic powder, salt, and black pepper.
Divide the meat mixture evenly into the muffin tin, shaping them into muffin-sized portions.
Brush the tops of the meatloaf muffins with a little extra ketchup for a flavorful glaze.
Bake in the preheated oven for 20-25 minutes or until the meatloaf muffins are cooked through and the tops are caramelized.
Remove from the oven, let them cool for a few minutes, and then serve your delicious Meatloaf Muffins.