In a large bowl, combine the egg, 3/4 cup cereal, onion, salt and pepper. Crumble beef over mixture and mix well.
For sauce, in a small bowl, combine the remaining ingredients. Add 2 tablespoons sauce to meat mixture; mix well. Shape into 1-1/2-in. balls.
Place meatballs on a rack coated with cooking spray in a shallow baking pan. Brush with remaining sauce; sprinkle with remaining cereal. Bake, uncovered, at 400° for 20-25 minutes or until no longer pink; drain.