In a pot, heat olive oil over medium heat.
Add garlic and onions to it and saute them for 5 minutes.
When garlic and onions are sauteed, add ground beef and sausage to it. Cook them until they turn brown.
Remove one-fourth fat from the mixture. Add tomato sauce, tomatoes, salt, pepper, Italian seasoning, and red pepper. Simmer the mixture for 30 minutes. Remove some cups of sauce to a bowl to cool down.
In a large pot, add water with salt. Cook the ziti until it will turn brown.
At 375oF, preheat the oven.
Add grated mozzarella, salt, pepper, ricotta, parmesan, parsley, and eggs. Stir the mixture accordingly.
Under the cool water, drain the pasta.
Add the pasta to the cheese mixture and toss it slightly. Then, add the reserved meat sauce and mix it properly.
In a large casserole dish, add half coated pasta and sauce over the pasta with mozzarella.
Again, add a layer coated pasta with sauce and mozzarella.
For 20 minutes, bake it and leave it for 5 minutes. Sprinkle chopped parsley over it and serve.