Burgers with a Bacon and Onion Whiskey Sauce

1. In a large bowl, mix the ground beef with the salt, and pepper. Divide the mixture into four equal portions, and then shape into 4 burger patties -- each about 4 inches in diameter.
2. Prepare the bacon and onion whiskey sauce. In a skillet, cook the bacon until crispy, then remove the bacon and let drain on a paper towel-lined plate. Reserve between 1-2 tablespoons of bacon grease in the skillet for cooking the onions. Carefully discard any excess bacon grease.
3. Slice the onions pole-to-pole, then cook the onions in the reserved bacon grease until they begin to brown and caramelize.
4. Sprinkle the cooked onions with the brown sugar, salt, pepper, and Worcestershire sauce. Cook until the sugar is dissolved. Add the whiskey, and let the mixture bubble and cook for a few more minutes. Set the saucy onions aside until ready to assemble the burgers.
5. Grill the burgers on a medium-hot, well-oiled grill, or on a cast iron griddle for about 4 minutes per side until the internal temperature reaches 160F.
6. Once the burger has cooked, add a slice of sharp white cheddar cheese to each burger, and let melt. Place the cooked burgers on a clean plate and let rest them for five minutes.
7. While the burgers are resting, grill the buns until lightly toasted.
8. Assemble the burgers. Place a handful of arugula on the bottom bun. Add the grilled beef patty (with the melted cheese). Layer on a few slices of bacon, then spoon on the onion whiskey sauce. Top with the other bun half (slathered with mayonnaise if desired). Serve while hot.

Bacon and Onion Whiskey Sauce:

• 4 slices bacon, cooked and cut in half (reserve 1-2 tablespoons of bacon grease)
• 1 sweet onion, sliced pole-to-pole
• 1/3 cup brown sugar
• 1/2 teaspoon Kosher salt
• 1/2 teaspoon pepper
• 1 teaspoon Worcestershire sauce
• 1 ounce whiskey