Preheat oven to 375 degrees F
Bring water to boil in 4-quart sauce pan, salt well. Add pasta and cook until al dente. I usually cook a minute or two LESS than the suggested cooking time.
While pasta is cooking, in a large mixing bowl stir together 1 ½ cups of sauce, ricotta cheese, 1 ½ cups mozzarella, parsley and egg.
When pasta is cooked, drain and then fold into the cheese/sauce mixture.
Prepare 4 quart baking dish (a 9x13” pan usually works great) by spreading ½ cup of the remaining tomato sauce on bottom of the dish. Pour in pasta mixture and then top with remaining sauce. Finally, sprinkle remaining shredded mozzarella over the top. Sometimes I also spread about ½ C of Parmigiano-Reggiano over the top.
Bake at 375°F for 30-35minutes or until bubbly and slightly browned on top. Let rest about 5 minutes or so before serving.