Preheat your oven to 375°F (190°C) and lightly grease a 9x13-inch baking dish.

Boil water in a large pot, season with salt, add ziti pasta, and cook for 7-8 minutes until very al dente. Drain and set aside.

In a large skillet, heat olive oil over medium-high heat, add ground Italian sausage and onion, cooking until browned and onion is soft.

Add minced garlic to the skillet and sauté for another minute. Then stir in marinara sauce and let it simmer for 5 minutes.

In a mixing bowl, combine ricotta cheese, egg, parsley, 1 cup of mozzarella, and Parmesan. Season with salt and black pepper.

Add the cooked ziti to the cheese filling and mix gently until well coated.

Spread half of the meat sauce in the greased baking dish, layer with the ziti mixture, then top with remaining sauce.

Sprinkle the remaining mozzarella cheese over the top.

Cover with foil and bake for 20 minutes, then remove foil and bake for an additional 15-20 minutes.

Let the baked ziti cool for 10 minutes before serving.

Serve warm and enjoy your ultimate easy baked ziti!