Cook the bacon: Place the diced bacon over medium heat in a big pan that measures at least 10 inches, ideally cast iron. Fry the bacon bits until they are perfectly crisp, rotating them occasionally. Do not turn off the heat. Next, take the crisp bacon with a slotted spatula and place it on a dish covered with paper towels.
To caramelize the onions, put the sliced onion to the skillet with enough of rendered bacon fat and toss to coat the onion slices in the grease. Turn the heat down to a medium level. Simmer the onions for approximately 25 to 30 minutes, or until they are soft and golden, tossing them occasionally to ensure equal cooking. It will take some time for onions to break down and completely caramelize when done correctly; take care not to overcook them.
Prepare the bacon burgers in the interim: Ground beef, Worcestershire sauce, mustard, garlic powder, old bay, salt, pepper, and the bacon bits that were set aside should all be combined in a big dish. Gently mix the ingredients with your hands (using disposable gloves if preferred) until it's just incorporated. Be cautious not to overmix the burger mixture as this can result in tough burgers.
Divide the ingredients for the bacon burgers into four equal parts. Flatten each part into a 1-inch-thick burger patty using your hands. After that, place the burgers on a dish or plate.
Going back to the onions, make a well in the middle of the pan once they get brown. Pour in the bourbon to deglaze, then whisk in the onions for approximately 30 seconds, using a wooden spoon to scrape off any crumbs. After that, add the maple syrup and mix everything together. Take out of the skillet and place the caramelized onions with maple and bourbon aside. Wipe the skillet down carefully.
Cook the bacon burgers by adding oil to the skillet and heating it all the way through on medium-high heat. Directly place the bacon burger patties into the skillet, leaving a small gap between each one. Note: To prevent packing the pan too full, make the patties in batches if you can't fit them all in. Cook for 3–4 minutes on each side, or until done to your preferred consistency, till golden and slightly charred. We want to retain all of the taste and juicy goodness of the burgers, so avoid mashing or pressing them down while they cook!
Top each burger with a piece of cheese when the cooking time reaches one minute remaining. To let the cheese steam and get extra melty, I prefer to cover the pan with a lid or other heatproof item. Before assembling the bacon burgers, move them to a fresh dish or platter and let them a few minutes to rest.
Serve: Top the bacon burgers, as preferred, with lettuce, tomatoes, mayonnaise, mustard, and a dollop of the maple-bourbon caramelized onions that were set aside on gently toasted buns. If preferred, serve burgers with your preferred side dishes. Have fun!