Cook the Shells:

• Cook pasta shells according to package instructions until al dente.

• Drain and set aside on a tray or towel to cool.

Prepare the Filling:

• In a large skillet, heat olive oil over medium heat.

• Sauté onion, bell pepper, and mushrooms (if using) until softened, about 5 minutes.

• Add ground beef or steak, cooking until browned. Drain excess fat.

• Stir in Worcestershire sauce, garlic powder, salt, and pepper. Remove from heat.

• Mix in provolone (or mozzarella) cheese until melted and combined.

Preheat Oven:

• Preheat oven to 350°F (175°C).

• Lightly grease a 9×13-inch baking dish.

Stuff the Shells:

• Fill each cooked shell with the cheesesteak mixture.

• Arrange in the baking dish. Pour Alfredo sauce evenly over the shells.

• Sprinkle with shredded cheddar cheese.

Bake:

• Cover with foil and bake for 20 minutes.

• Remove foil and bake another 10 minutes, or until cheese is bubbly and golden.

Serve:

• Garnish with chopped parsley and serve hot.