**Cook the Beef:** Heat a large skillet over medium-high heat. Add the ground beef and cook until browned, breaking it up with a spoon. Drain excess fat if needed.

**Sauté Vegetables:** Add the onion and bell pepper to the skillet with the beef. Cook for 4-5 minutes, or until softened. Stir in the garlic and cook for 1 more minute.

**Season the Mixture:** Stir in the Worcestershire sauce, ketchup, and beef broth. Simmer for 3-5 minutes to let the flavors meld. If the mixture is too thin, stir in the cornstarch slurry and cook until thickened. Season with salt and pepper to taste.

**Melt the Cheese:** Lay the provolone cheese slices over the meat mixture in the skillet. Cover with a lid and let the cheese melt for 1-2 minutes.

**Assemble the Sandwiches:** Spoon the cheesy beef mixture onto the toasted buns. Add any optional toppings if desired.

**Serve:** Serve warm with your favorite side dishes like fries or a crisp salad.