Ingredients
1/4 cup ketchup1/4 cup finely chopped onion4 teaspoons prepared mustard2 teaspoons salt1 teaspoon pepper4 pounds ground beef1-1/2 cups shredded cheddar cheese12 hamburger buns, split
Preparation
In a large bowl, combine the first five ingredients. Crumble beef over mixture and mix well. Shape into 24 thin patties. Sprinkle cheese in the center of 12 patties; top with remaining patties and press edges firmly to seal.
Grill, covered, over medium heat or broil 4 in. from the heat for 6-9 minutes on each side or until no longer pink. Serve on buns.
