Preheat the Oven: Preheat your oven to 350°F (175°C). Grease a 9×13-inch casserole dish and set aside.

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 and toss with olive oil to prevent sticking. Set aside.

Brown the Ground Beef: In a large skillet over medium heat, cook the ground beef until browned and fully cooked, about 5-7 minutes. Drain any excess fat.

Add the Sauce: Add the marinara sauce to the beef and stir to combine. Let it simmer for 5 minutes. Season with salt and pepper to taste.

Prepare the Cream Cheese Mixture: In a medium bowl, combine the softened cream cheese, sour cream, ricotta cheese, garlic powder, Italian seasoning, and half of the Parmesan cheese. Mix until smooth and creamy.

Assemble the Casserole: Spread a thin layer of the meat sauce on the bottom of the prepared casserole dish. Add the cooked spaghetti to the dish, spreading it evenly. Spread the cream cheese mixture over the spaghetti in an even layer. Pour the remaining meat sauce over the cream cheese layer. Top with shredded mozzarella and the remaining Parmesan cheese.

Bake the Casserole: Cover the casserole with foil and bake in the preheated oven for 25-30 minutes, until the cheese is melted and bubbly. Remove the foil and bake for an additional 5-10 minutes, or until the cheese on top is golden brown.

Serve: Remove the casserole from the oven and let it cool slightly before serving. Garnish with fresh parsley, if desired, and serve warm