Lightly spray a rimmed baking sheet with cooking spray.
Lightly beat the eggs in the bottom of a large bowl. Place the burger on top of the eggs and then add the bread crumbs, salt, pepper, and garlic powder; using your hands’ mix until thoroughly combined.
Divide meat mixture into 12 – 2-inch meatballs and place on the baking sheet. Bake for 15 minutes or until an instant-read thermometer reads an internal temperature of 160F, and meatballs are browned. Remove meatballs to a plate and discard any accumulated fat. Line now-empty baking sheet with parchment paper, slice buns, and place 3 meatballs on each bun. Pour 1/3 cup marinara sauce over the meatballs on each bun and top with a slice of cheese. Return to the oven and cook until heated through and cheese is melted – serve hot.