The Caprese Burger: an all-beef patty stuffed with gooey melted mozzarella cheese, topped with balsamic onions, sliced tomato, and fresh basil all sandwiched between a buttery brioche bun. It is absolute perfection!
Add 2 pounds ground beef to a large mixing bowl along with 2 tablespoons Worcestershire sauce, 1 teaspoon salt, and 1 teaspoon black pepper. Gently need together to combine.
Divide into 8 portions. Take a portion into your hand and flatten it quite thin, about 1/4-inch. Place a slice or two (1 ounce) of your 4 ounces fresh mozzarella in the middle and lay it on a plate or tray or piece of parchment paper. Take another portion and flatten it out just as thin. Place it on top of the mozzarella and pinch the sides all around it to seal the mozzarella in the middle. Repeat with remaining portions to form 4 burger patties.
Heat a large heavy skillet or grill pan over medium-high heat. Cook burgers for about 5 minutes per side for medium, 6 to 7 minutes per side for medium-well, and about 8 minutes per side for well-done. Ground beef in the United States needs to be cooked to an internal temperature of 145 degrees Fahrenheit.
Meanwhile, make your balsamic onions by heating 1 tablespoon olive oil in a separate large skillet over medium-high heat. Add in 1 sliced white onionand saute for about 5 minutes until onions start to soften. Pour in 1/4 cup balsamic vinegar, reduce heat to medium, and continue cooking until onions have soaked up balsamic vinegar, about 5 minutes more. Set aside until ready to serve.
Serve the burgers hot on 4 brioche hamburger buns topped with a slice or two of tomato, a heaping pile of balsamic onions, and fresh basil leaves.