n a large bowl, combine ground sirloin, ground chuck, Worcestershire sauce, steak seasoning and crumbled bacon; shape into eight patties slightly larger than the buns, place on a foil-lined sheet pan, cover and chill for one hour.

Melt butter over medium-low heat in a saucepan, stir in onions, black pepper and brown sugar, then cook for 5 minutes, stirring frequently. Remove from heat, mix in bourbon (if using), return to low heat and continue cooking until onions are a deep golden brown, about 15 minutes. Transfer to a bowl and set aside.

Preheat grill. Cook patties for 1–2 minutes per side or until they reach the desired doneness, then move to a cooler rack. Top each patty with 1–2 slices of cheddar, cover the grill and allow the cheese to melt, about 1–2 minutes. Transfer to a tray and keep warm.

Spread 1 tablespoon of barbecue sauce on each bun bottom. Layer one cheeseburger, 1 tablespoon of caramelized onions, a second cheeseburger, another tablespoon of onions, then the final cheeseburger. Drizzle with extra barbecue sauce, cap with the bun tops and serve with chips and pickles.