Combine the crushed tomatoes, tomato puree, tomato sauce, tomato paste, Italian seasoning, garlic powder, and onion powder in a large bowl. You can also use your favorite tomato sauce instead, you just need around 9 cups of sauce.

In a smaller bowl, stir together the ricotta cheese, eggs and basil leaves. Season with salt and pepper.

When ready to assemble, brush the inside of your slow cooker with olive oil. Add 2 1/2 cups to the pasta sauce of the bottom of your slow cooker and spread evenly.

Sprinkle in ~1/3 of the ziti.

Add on half of the ricotta mixture in dollops.

Evenly sprinkle 1/2 cup of the parmesan cheese.

Add another layer of tomato sauce using 2 1/2 cups of the sauce.

Sprinkle another 1/3 of the ziti on top.

Add the rest of the ricotta mixture.

Sprinkle with the remaining 1/2 cup of parmesan cheese.

Add another layer of tomato sauce, about 2 cups.

Add the last 1/3 of the ziti.

Top with the remaining 2 cups of sauce.

Cover and cook on high for 2 1/2 hours.

When ready to serve, remove the top and sprinkle with the mozzarella cheese. Cover and cook for another 5 minutes, or until the mozzarella has melted.

Serve.

Top with more chopped fresh basil, if desired.