Creating the delightful Philly Tomato Pie is a straightforward process when you follow these steps:

1. Preheat Oven: Start by preheating your oven to 375°F (190°C).
2. Prepare the Pie Crust: Roll out your pre-made pie crust and fit it into a 9-inch pie plate. Trim any excess edges and prick the bottom with a fork.
3. Sauté the Onions and Garlic: In a skillet over medium heat, add a drizzle of olive oil. Sauté the chopped onions and minced garlic until softened and fragrant, about 3-5 minutes. Remove from heat and let cool slightly.
4. Mix the Filling: In a large bowl, combine the diced tomatoes, sautéed onion and garlic, mozzarella cheese, Parmesan cheese, fresh basil, oregano, sugar, salt, and pepper. Stir well to incorporate all ingredients.
5. Fill the Pie Crust: Pour the tomato mixture into the prepared pie crust, spreading it evenly.
6. Prepare the Egg Wash: Beat the egg in a small bowl. Use a pastry brush to apply the egg wash around the edges of the pie crust for a beautiful golden finish.
7. Bake: Place the pie in the preheated oven and bake for 30-35 minutes, or until the crust is golden brown and the filling is bubbling.
8. Cool: Remove the pie from the oven and let it cool for 10-15 minutes before slicing.

These steps will guide you in creating an incredible Philly Tomato Pie that is both delicious and satisfying!