01 -  In a bowl, combine ricotta cheese, egg, salt, and pepper until thoroughly blended. 
 02 -  In a large bowl, toss the cooked ziti with half of the marinara sauce until coated. 
 03 -  Spread half of the pasta mixture into a baking dish. Top evenly with ricotta mixture, half of the mozzarella, and remaining pasta. Pour over the remaining marinara sauce and sprinkle with the remaining mozzarella. 
 04 -  Sprinkle grated Parmesan cheese over the top. Cover the dish with aluminum foil. 
 05 -  Place the assembled dish in the freezer until ready to bake. 
 06 -  When ready to serve, bake the covered frozen casserole at 375°F (190°C) for 50–60 minutes, or until hot and bubbling throughout.