Preheat your oven to 350°F (175°C).

Cook spaghetti according to package instructions until al dente; drain and set aside.

In a large skillet, heat olive oil over medium heat and sauté ground beef until browned.

Drain excess fat, then stir in marinara sauce; simmer for 10 minutes.

In a large bowl, mix ricotta cheese, sour cream, and half of the mozzarella.

Season the cheese mixture with salt, pepper, and chopped parsley.

In a baking dish, layer half of the spaghetti, followed by half of the meat sauce.

Spread the cheese mixture over the meat sauce layer.

Add the remaining spaghetti and top with the rest of the meat sauce.

Finish by sprinkling the remaining mozzarella and Parmesan cheese on top.

Cover with foil and bake for 30 minutes, then remove the foil and bake for an additional 10-15 minutes until bubbly and golden.