Preheat your oven to 375°F (190°C).
In a skillet, sauté onions and garlic over medium heat until soft.
In a mixing bowl, combine ground beef, breadcrumbs, milk, egg, sautéed onions and garlic, ketchup, salt, black pepper, and optional vegetables.
Grease a muffin tin and scoop the meat mixture into each cup, filling them about three-quarters full.
Top each meatloaf cup with a small dollop of ketchup for flavor and moisture.
Bake in the preheated oven for 25-30 minutes until cooked through and internal temperature reaches 160°F (70°C).
Allow to cool slightly before removing them from the muffin tin.
Serve warm with your favorite sides or on their own!