In a large bowl, combine the thinly sliced flank steak with garlic powder, salt, pepper, and Worcestershire sauce (if using). Allow it to marinate for about 15-20 minutes.
While the steak marinates, slice the onion and bell pepper.
In a large skillet, heat 1 tablespoon of olive oil over medium heat. Add the sliced onions and bell peppers and cook for about 5-7 minutes, or until they are softened and slightly caramelized. Remove them from the skillet and set aside.
In the same skillet, add the remaining tablespoon of olive oil. Increase the heat to high and add the marinated steak. Cook for 2-3 minutes, stirring frequently until browned and cooked to your desired doneness.
Return the sautéed vegetables to the skillet with the steak, mixing everything together. Cook for an additional minute to combine the flavors.
Place the provolone cheese slices on top of the steak and vegetable mixture. Cover the skillet with a lid to help melt the cheese, about 1-2 minutes.
While the cheese melts, lightly toast the hoagie rolls in the oven or on a pan until golden brown.
Spoon the cheesy steak and vegetable mixture into the toasted rolls.
Sprinkle chopped fresh parsley on top for garnish. Serve hot and enjoy your gourmet Philly cheesesteak!
Notes
Feel free to customize the cheese and add other toppings as desired.