Place ground beef into a large mixing bowl then add salt, pepper and Worcestershire sauce. Mix until seasonings are distributed evenly and combined. Divide meat into 6 equal-sized portions and form into patties slightly larger in diameter than buns. Set aside.
Heat a large skillet over medium heat. Add bacon and fry to desired crispness. Transfer bacon to a paper towel lined plate and set aside. Drain bacon grease from skillet, return to stove and heat to medium-high.
Add as many hamburger patties to skillet, that will fit without crowding—it’s okay to work in batches when frying the patties. Cook for approximately 3–4 minutes per side—until brown and crispy on the outside and slightly underdone in the middle. Remove patties from skillet then set aside. Drain all but about 2 tablespoons of grease then return skillet to stove.
Add onions to skillet, reduce heat to medium then cook for about 3 minutes until onions are tender and translucent.
Remove skillet from heat then add whiskey. Return skillet to heat. Allow whiskey to reduce until nearly all of the liquid (and alcohol) has evaporated then stir in barbecue sauce.
Reduce heat to low, return hamburger patties to skillet, completely coating them in sauce. Cook to desired temperature while simmering in sauce. If sauce becomes too thick, stir in a bit of water to keep it from scorching.
Place one slice of smoked cheddar cheese over each burger until it starts to melt. Transfer patties to toasted buns, add 1 slice of bacon and sliced red onion to each burger . Serve extra whiskey barbecue sauce on the side. Enjoy!
Notes
Keep in mind when you’re cooking the burgers to never add alcohol directly to a pan that’s over a flame. High alcohol content liquors such as whiskey can easily ignite.