Creating Cheesy Low Carb Philly Cheesesteak Casserole involves straightforward steps that ensure a flavorful outcome. Follow these instructions:

1. Preheat Oven: Preheat your oven to 350°F (175°C).
2. Cook the Beef: In a large skillet over medium heat, add olive oil. Once hot, add the ground beef and cook until browned, breaking it apart with a spatula. Season with salt and pepper. Drain excess fat if needed.
3. Add Vegetables: Add the sliced onions, bell peppers, and mushrooms (if using) to the skillet. Cook until they are tender, about 5-7 minutes. Add minced garlic and cook for another minute.
4. Mix in Cream: Pour the heavy cream and Worcestershire sauce into the skillet. Stir well to combine all ingredients.
5. Add Cheese: Stir in half of the provolone and mozzarella cheese, mixing until melted and creamy.
6. Transfer to Baking Dish: Pour the meat and vegetable mixture into a greased 9×13-inch baking dish, spreading it evenly.
7. Top with Cheese: Sprinkle the remaining provolone and mozzarella cheese on top of the casserole.
8. Bake: Place the dish in the preheated oven and bake for 25-30 minutes or until the cheese is bubbly and golden brown on top.
9. Garnish: Remove from the oven and let it cool for a few minutes. Garnish with fresh parsley before serving.
10. Serve: Scoop portions onto plates and enjoy your delicious, cheesy, low-carb casserole.

These steps ensure that your Cheesy Low Carb Philly Cheesesteak Casserole turns out perfectly every time!