Step 1

In a large skillet, melt the 3 tablespoons of butter over medium heat.

Step 2

Add the 1/4 cup bourbon, onions, sugar, salt and pepper.

Step 3

Cook, stirring occasionally until the onions are soft and lightly browned, at least 20 minutes.

Step 4

Meanwhile, add the ground beef to a large bowl with the 3 tablespoons bourbon, Worcestershire sauce, cumin, oregano, salt and pepper. Lightly mix with your hands and form into six patties.

Step 5

Heat grill and scrape the grates clean. Cook the burgers, searing on the higher heat side and flipping to finish cooking on the lower heat side. Cook the burgers until the internal temperature is 145 degrees F for medium rare or 160 degrees F for medium.

Step 6

Add a slice of the Provolone cheese to the top of each burger in the last minute of cooking to melt.

Step 7

Serve the burgers topped with the caramelized onions and fresh leaf lettuce.