cheddar cheese, shredded
In a large bowl, combine the first six ingredients; mix well.
Shape into 12 thin patties.
Broil 4 inches from the heat for 7-8 minutes on each side or until no longer pink.
In a small bowl, combine cheese, mayonnaise, mustard and relish; mix well.
Spoon 2 tablespoons of mixture on each burger.
Return to the broiler just until cheese softens.
Place lettuce and onion on bottom of buns; top each with two burgers, tomato and top of bun.