Preheat oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish.

Cook rotini pasta according to package directions. Drain and set aside.

In a large skillet, cook the ground beef with diced onion and garlic over medium heat until the beef is browned. Drain excess fat.

Stir in marinara sauce, and season with salt, pepper, and Italian seasoning. Simmer for 5 minutes.

In a large bowl, mix ricotta cheese, 1 cup of mozzarella, Parmesan, egg, salt, and pepper until smooth.

Add the cooked rotini to the meat sauce, and stir until well combined.

Layer half of the pasta mixture in the prepared baking dish. Spread the ricotta mixture evenly over the top, then add the remaining pasta mixture.

Sprinkle the remaining mozzarella on top.

Cover the dish with aluminum foil and bake for 25 minutes.

Remove the foil and bake for another 10 minutes, until the cheese is golden and bubbly.

Garnish with fresh parsley if desired and serve warm!