Cook the Spaghetti
Preheat your oven to 375°F (190°C).
Boil spaghetti in salted water according to package instructions. Drain and set aside.
Prepare the Meat Sauce (Optional)
Heat olive oil in a skillet over medium heat. Add ground beef or turkey and cook until browned.
Stir in marinara sauce, garlic powder, Italian seasoning, and salt and pepper. Simmer for 5 minutes.
Make the Cream Cheese Layer
In a mixing bowl, combine softened cream cheese with ¼ cup of the marinara sauce and a splash of the pasta water. Stir until smooth and creamy.
Assemble the Casserole
Spread a thin layer of the meat sauce on the bottom of the baking dish.
Toss the cooked spaghetti with the cream cheese mixture until well coated.
Layer the spaghetti over the meat sauce.
Top the spaghetti with the remaining meat sauce.
Sprinkle mozzarella and Parmesan cheeses evenly over the top.
Bake
Cover the dish with foil and bake for 20 minutes.
Remove the foil and bake for an additional 10 minutes, or until the cheese is bubbly and golden.
Serve
Let the casserole rest for 5 minutes before serving. Enjoy warm!