In A Large Bowl, Combine The First Four Ingredients. Crumble Beef Over The Mixture And Mix Well. Shape Into Six 1/2-In. Thick Patties; Place On An Ungreased Broiler Pan. Broil 4 In. From The Heat For 7-9 Minutes On Each Side Or Until No Longer Pink. Top Each With A Cheese Slice. Broil 1-2 Minutes Longer Or Until Cheese Is Melted. Serve On Buns With Lettuce And Tomato Slices.