Bacon Burgers with Balsamic Caramelized Onions

Bahan-bahan (4 porsi)

• 4 slices applewood smoked bacon, (cut crosswise into 1/2-inch strips)
• 1 large sweet onion, (thinly sliced)
• kosher salt and freshly ground black pepper
• ⅓ cup balsamic vinegar
• ⅓ cup water
• 1 teaspoon Dijon mustard
• 2 slices applewood smoked bacon, (chopped finely)
• 24 ounces 85% lean ground beef
• ½ teaspoon Worcestershire sauce
• kosher salt and freshly ground black pepper