Preparation

• In a large bowl, mix the beef, bacon, Worcestershire sauce and 1 teaspoon pepper. Divide into 4 even portions, form into 1-inch thick patties and set aside.
• To a cast-iron skillet over medium heat, add the mushrooms and 2 tablespoons butter. Cook until the mushrooms are golden-brown, 7 to 10 minutes. Add the bourbon and cook until the liquid is reduced by half, 4 to 5 minutes. Season to taste with salt and pepper. Transfer to a bowl and cover.
• Increase the heat to medium-high and add the remaining 4 tablespoons butter. Swirl the skillet until the butter becomes a deep golden-brown, about 5 minutes. Add the patties and cook until seared and cooked through, 3 to 4 minutes per side for medium doneness.
• Divide the cheese between the patties and cover the skillet. When the cheese has melted, place the patties on the toasted buns and top each with the mushrooms.