Wash and dice the bell peppers and onion into small pieces. Mince the garlic cloves. Having everything ready before cooking makes the process faster and much easier.

Heat olive oil in a large skillet over medium heat. Add the peppers and onion. Cook for about five minutes until they become soft and slightly golden.

Stir the minced garlic into the skillet. Cook for one minute. Garlic cooks quickly, so keep stirring to prevent burning and maintain its delicious flavor.

Add the ground beef to the skillet. Break it apart with a wooden spoon. Cook until fully browned and no longer pink. Drain excess grease if needed.

Mix in Worcestershire sauce, ketchup, Dijon mustard, salt and black pepper. Stir well so every bite gets coated with the flavorful mixture.

Add the beef broth and stir everything together. Bring the mixture to a gentle simmer. This helps the flavors blend and creates a rich filling.

Mix cornstarch and water in a small bowl. Pour into the skillet. Stir constantly until the mixture thickens slightly and becomes rich and hearty.

Lower the heat and sprinkle in the shredded provolone cheese. Stir until melted completely. The cheese creates a creamy texture that makes the filling irresistible.

Lightly toast the hamburger buns in a skillet or oven. Toasting helps prevent the bread from becoming soggy once the filling is added.

Spoon the cheesy beef mixture onto each bun. Garnish with fresh parsley if desired. Serve immediately while warm and enjoy every cheesy bite.