Mix together the ground beef, steak seasoning, and Worcestershire sauce. Form into even patties.
Once hot, grill or cook burgers on both sides getting a nice crusty char to desired doneness (see below) using a thermometer. When the burger is 3/4 of the way cooked to your liking, add the cheese and melt.
Lightly toast the buns.
Top the burger with onion. Serve with pickle and ketchup or your choice of condiments.