1.In A Large Bowl, Combine Beef, Onion, Egg And Ketchup. Season With Salt, Pepper, Oregano, And Worcestershire Sauce. Lightly Mix In Cheddar Cheese. Shape Beef Mixture Into 6 Thick Patties. Preheat Oven On Broiler Setting. 2.Place Hamburgers On Broiler Pan. Broil, Turning Once, Until Cooked Through, About 5 Minutes Per Side. Serve On Hamburger Buns.