In a skillet over medium heat, cook the ground beef until browned, breaking it apart with a spatula.

Add the diced onion, green bell pepper, and minced garlic to the skillet. Cook until the vegetables are soft, about 5 minutes.

Stir in the beef broth, Worcestershire sauce, salt, and black pepper. Bring to a simmer and let cook for 10 minutes, allowing the sauce to thicken.

Spoon the meat mixture onto the burger buns. Top with shredded provolone cheese.

Serve immediately while the cheese is melty.