How to Make It
Place beans in large bowl; mash with a potato masher. Add beef, Worcestershire, chili powder, salt and pepper. Gently mix to combine.
Form 8 thin patties. Cut each slice of cheese into for equal squares; stack the pieces. Sandwich one stack of cheese between 2 meat patties. Tightly pinch edges together to seal. Repeat with remaining patties and cheese.
Heat a cast-iron or stovetop grill skillet over medium heat. Cook burgers for about 8 minutes, turning once, until browned and no longer pink inside. Serve on onion rolls with favorite condiments.
Mix remaining black beans with some jarred tomato salsa to serve over burgers.