Preheat the oven to 375°F (190°C). Bring a large pot of salted water to a boil.
Cook the ziti in the boiling water according to package instructions until al dente (about 9–11 minutes). Drain and set aside.
In a large bowl, beat the eggs, then add the ricotta and stir until smooth.
Add 1 cup of the mozzarella, 1/2 cup of the parmesan, Italian seasoning, parsley, salt, pepper, and minced garlic to the ricotta mixture and mix until combined.
Toss the drained pasta with the ricotta-cheese mixture until the pasta is evenly coated.
Lightly oil or spray a 9×13-inch baking dish. Spread about half the marinara sauce (about 2 cups) on the bottom of the dish.
Transfer the cheesy pasta into the baking dish and spread evenly, then spoon the remaining marinara sauce over the top.
Sprinkle the remaining 1 cup mozzarella and 1/2 cup parmesan evenly over the sauce.
Cover the dish with foil and bake for 20–25 minutes until the sauce is bubbling and the cheeses are melted.
If desired, remove the foil and bake an additional 3–5 minutes to brown the top. Let the casserole rest for 5 minutes before serving.
