Heat the oil in a saucepan on medium heat.
Soak the onion in cold water for 2 - 3 minutes. Drain and coat the onions well in the flour.
Fry the onions in the oil until golden brown and crispy. Transfer the onions to a paper towel lined plate and season with salt and pepper. Set Aside.
Preheat grill or grill pan on medium heat.
Mix together the ground beef, steak seasoning, and worchestershire sauce, season generously salt and pepper and form into patties. Grill burgers to desired doneness (see below) using a thermometer. When the burger is 3/4 of the way cooked to your liking add the cheese to the top to melt.
Lightly toast the buns on the grill or in an oven under a low broiler. Spread the BBQ sauce on the bun. Layer with lettuce, tomato, burger, and crispy onions. Serve with pickles.