Making your Philly Cheesesteak Casserole is a fun and relatively simple process. Follow these steps to ensure delicious results:

1. Preheat the Oven: Start by preheating your oven to 350°F (175°C). Grease a 9×13-inch casserole dish to prevent sticking.

2. Cook the Beef: In a large skillet over medium-high heat, add the olive oil. Once hot, add the sliced beef and cook for about 5 minutes, or until browned. Season with salt and pepper.

3. Sauté Vegetables: Add the sliced onion, bell pepper, and mushrooms (if using) to the skillet and cook for another 5-7 minutes, until the vegetables are softened. Stir in the minced garlic and cook for an additional minute.

4. Combine Ingredients: In a large mixing bowl, combine the cooked pasta, beef and vegetable mixture, Worcestershire sauce, and beef broth. Stir until everything is well mixed.

5. Layer in the Dish: Pour half of the mixture into the prepared casserole dish. Sprinkle half of the provolone cheese over this layer. Add the remaining beef and pasta mixture, then top with the remaining cheese.

6. Bake: Cover the casserole with aluminum foil (to prevent sticking), and bake for 30 minutes. Then, remove the foil and bake for an additional 10 minutes, or until the cheese is bubbly and golden.

7. Cool and Serve: Once done, remove the casserole from the oven and let it cool for about 5-10 minutes. Garnish with fresh parsley if desired.