Preheat oven to 350 degrees F.
In a large mixing bowl (using your hands or a large spoon), combine ground beef, breadcrumbs, onion, 1 Tbsp barbecue sauce, mustard, chili powder, garlic powder, salt, pepper and egg.
Divide the mixture among the 12 cups in a standard muffin tin, pressing them down to fill the cup. Bake for 15 minutes.
In the meantime, in a small bowl mix together all of the ingredients for the sauce.
Remove the meatloaf from oven and use a paper towel to soak up any grease on the meatloaf.
Generously spoon sauce over each mini meat loaf. Return to oven for an additional 10-15 minutes or until the meat is cooked through.
Serve with mashed potatoes and any extra sauce.