Directions:

1. Prepare the onions: In a large skillet, saute bacon over medium heat until lightly browned, but not crisp (8 minutes or so). Transfer bacon to paper towels to drain. Pour off all but 2 to 3 Tablespoons of bacon fat from the skillet. Add the onion, season lightly with salt and pepper, and cover the pan; cook for 2 minutes. Uncover, add a splash of water, scrape up any browned bits from the bottom of the pan. Cover, and continue to cook, stirring often, until the onions are soft and beginning to color- about 10 minutes. Add the vinegar, mustard and water. Return the bacon to the skillet and bring the mixture to simmer. Continue to simmer, uncovered, until the liquid has thickened and most of it has been absorbed- 2 to 4 minutes. Transfer to a small bowl and let cool. Leave at room temperature for up to 2 hours, or refrigerate for up to 2 days (reheating, as needed).

2. Make the burgers: In a large mixing bowl, use a fork to gently combine bacon, ground beef, worcestershire sauce, 1 teaspoon salt and 1/2 teaspoon pepper. Form into 4 hamburger patties, and press your thumb into the center of each patty to create a deep depression. Preheat your grill. Grill burgers to desired doneness (4 to 5 minutes per side). Toast the buns too, if desired.

3. Assemble the burgers: Serve the burgers on the buns topped with warm balsamic- caramelized onions. No additional condiments are needed!

Tips:

*Fine Cooking shared that making an indentation in the center of each burger keeps them from swelling up into mini basketballs on the grill. I love this tip!
*If preparing this recipe as gluten free, you'll obviously need GF hamburgers buns. Also, make sure you are using gluten free bacon, worcestershire sauce and Dijon mustard.