Prepare the Spaghetti Base

1. Cook the Spaghetti: Bring a large pot of salted water to a boil. Add the spaghetti and cook according to the package instructions until al dente. Drain the pasta and set aside.
2. Prepare the Spaghetti Mixture: In a large bowl, combine the cooked spaghetti, ricotta cheese, mozzarella cheese, Parmesan cheese, egg, salt, and pepper. Mix well until the pasta is coated evenly with the cheese mixture. The egg helps bind the ingredients together and gives the pie its structure.

Prepare the Meat Sauce

1. Cook the Meat: Heat a large skillet over medium heat and add the ground beef (or turkey). Cook until browned, breaking it apart with a spoon as it cooks. Drain any excess fat if needed.
2. Add the Vegetables and Seasonings: Add the chopped onion and minced garlic to the pan. Sauté for about 3-4 minutes until the onion is soft and fragrant. Stir in the marinara sauce, basil, oregano, salt, and pepper. Simmer for 5-10 minutes, allowing the flavors to meld together.

Assemble the Pie

1. Preheat the Oven: Preheat your oven to 375°F (190°C).
2. Layer the Spaghetti Base: Grease a 9-inch pie dish or a similar-sized casserole dish. Spread the spaghetti mixture evenly at the bottom of the dish, pressing it down gently to form a base.
3. Add the Meat Sauce: Spoon the prepared meat sauce over the spaghetti base, spreading it out evenly to cover the noodles.
4. Top with Cheese: Sprinkle the shredded mozzarella cheese on top of the meat sauce for that perfect, gooey finish.

Bake the Spaghetti Pie

1. Bake: Place the assembled spaghetti pie in the preheated oven and bake for 30 minutes, or until the cheese is bubbly and golden brown on top.
2. Cool and Serve: Allow the pie to cool for about 5 minutes before slicing. This helps the layers set so you can cut clean slices. Garnish with fresh basil or parsley if desired.