1. In a large skillet over medium-high heat, add the olive oil and allow it to heat up for about a minute.
2. Add the chopped onion and bell pepper, sautéing until they become tender and the onions are translucent, about 5 minutes.
3. Stir in the minced garlic and cook for another 30 seconds until fragrant.
4. Add the ground beef to the skillet, breaking it apart with a spoon as it browns. Cook until no pink remains, about 7-8 minutes.
5. Drain excess fat from the skillet, then return it to the heat.
6. Pour in the beef broth, Worcestershire sauce, and ketchup, stirring to combine.
7. Bring the mixture to a simmer, then stir in the cornstarch slurry to thicken the sauce. Season with salt and pepper to taste.
8. Lay the provolone slices over the beef mixture, allowing them to melt slowly. Gently stir to incorporate the cheese throughout the mixture.
9. Toast the hamburger buns, if desired, and then spoon the beef mixture onto the bottom halves. Place the top halves on the sandwiches and serve immediately.

Pro Tip: Don’t shy away from adding your favorite toppings. Sautéed mushrooms or jalapeños can add an extra layer of flavor to elevate this dish even more.