Preheat your oven to 375°F (190°C).

Cook the ziti pasta according to package instructions until al dente. Drain and set aside.

In a large skillet over medium heat, brown the ground beef with the diced onion and minced garlic until the beef is cooked through. Drain any excess fat.

Stir in the marinara sauce, Italian seasoning, salt, and black pepper. Let it simmer for about 5 minutes.

In a large bowl, combine the cooked ziti, meat sauce mixture, ricotta cheese, and half of the mozzarella and Parmesan cheeses. Mix well until everything is evenly coated.

Transfer the mixture to a greased 9x13 inch baking dish. Sprinkle the remaining mozzarella and Parmesan cheeses on top.

Cover the dish with aluminum foil and bake for 25 minutes. Remove the foil and bake for an additional 15 minutes, or until the cheese is bubbly and golden.

Let it cool for 5-10 minutes before serving. Garnish with fresh parsley if desired.