Cook the ziti in salted boiling water until just al dente. Drain and set aside, making sure not to overcook since it will bake later. Toss lightly with a bit of olive oil to prevent sticking.
Heat olive oil in a skillet and sauté onions until soft, then add garlic. Stir in the ground beef and cook until browned, breaking it apart. Add marinara sauce, seasoning, salt, and pepper, then let it simmer for a few minutes.
In a bowl, combine ricotta cheese, egg, and half of the Parmesan cheese. Mix until smooth and creamy. This layer adds a rich, velvety texture to the dish.
Spread a thin layer of meat sauce in the baking dish, then add half the pasta. Spoon half of the ricotta mixture over it, followed by mozzarella. Repeat the layers, finishing with sauce and a generous topping of cheese.
Cover the dish with foil and bake in a preheated oven at 375°F (190°C) for about 25 minutes. Remove the foil and bake for another 10 minutes until the cheese is melted and slightly golden.
Let the baked ziti rest for about 5–10 minutes before serving. This helps the layers set and makes it easier to slice and serve beautifully.