01 -
Preheat the oven to 375°F and grease a 9x13-inch baking dish.
02 -
In a skillet over medium heat, brown the Italian sausage and diced onion. Drain any excess fat.
03 -
Add pasta sauce, diced tomatoes with their juices, water, and Italian seasoning to the skillet. Simmer for about 12 minutes.
04 -
Cook the ziti pasta in salted boiling water until al dente. Drain well.
05 -
In a mixing bowl, combine ricotta cheese, a beaten egg, chopped fresh parsley, 1 cup of shredded mozzarella, and the shredded Parmesan cheese.
06 -
Spread 1 cup of the sauce mixture in the greased baking dish. Layer half of the cooked ziti over the sauce, followed by all of the ricotta cheese mixture, and then half of the remaining sauce.
07 -
Add the remaining ziti, top with the rest of the sauce, and sprinkle the remaining shredded mozzarella cheese on top.
08 -
Bake the assembled dish for 25-30 minutes, or until it is bubbly and golden brown on top.