Combine ground beef, Worcestershire sauce, salt and pepper. Form into 4 patties.
In a medium skillet, sauté onion in olive oil until nicely browned. Reserve.
Cook patties to desired doneness, remove from heat, top with cheeese, cover and allow to rest.
Build Patty Melt like you would a grilled cheese. Butter bread slices, layer burgers, cheese, sautéed onions, and grill both sides until golden brown.