Preheat the oven to 375 degrees . Grease 4 cups of a 6-cup jumbo muffin pan. In a saucepan of boiling, salted water, cook the sweet potato until partially cooked, about 3 minutes; drain.
Using a food processor, pulse the bread to form breadcrumbs; transfer to a large bowl. Add the beef, egg, onion, cilantro, chipotles, 1 tsp. adobo sauce, 2 tbsp. ketchup, the garlic, 1 1/4 tsp. salt and 1/4 tsp. pepper; stir to combine. Stir in the sweet potato. Divide the beef mixture among the greased muffin cups, packing well and mounding slightly.
In a small bowl, combine the remaining 4 tbsp. ketchup and 1 tsp. adobo sauce and coat the tops of the meatloaves with the mixture. Place the muffin pan on a baking sheet and bake until cooked through and browned on top, 40 minutes.