Preheat oven to 450 degrees and lightly grease a muffin pan.
Pulse onion in a food processor until finely chopped and juicy.
Combine ground beef, onion, egg, bread crumbs, garlic powder, onion powder, salt, and pepper in a large bowl.
In a smaller bowl, mix together barbecue sauce, maple syrup, bourbon, Worcestershire sauce, and yellow mustard. Pour 4 tablespoons of the sauce mixture into a small bowl and pour the remaining sauce into the meatloaf mixture.
Mix the meatloaf mixture together until combined. (I use my hands).
Scoop the mixture into the muffin pan using an ice cream scoop.
Top each mini meatloaf with the remaining 4 tablespoons of the sauce mixture and then spread it around on top.
Bake for about 20-25 minutes. Let cool in pan for 3-5 minutes before serving. Enjoy!