Cook the ziti pasta in salted boiling water until al dente, then drain.

Heat olive oil in a skillet and sauté chopped onion until translucent, then add garlic and cook until fragrant.

Add marinara sauce, season with salt and pepper, and let simmer for 10 minutes.

Mix ricotta, half of the mozzarella, and a bit of parmesan in a bowl.

In a baking dish, layer pasta, sauce, and cheese mixture. Repeat layers and top with remaining mozzarella and parmesan.

Cover with foil and bake at 375°F for 20 minutes. Uncover and bake another 10-15 minutes until the top is golden and bubbly.

Let rest for 5 minutes before serving. Garnish with fresh basil or parsley if desired.