Cook the ziti pasta according to package instructions, in a large pot of salted boiling water until al dente. Drain and rinse with cold water to stop the cooking process and prevent the pasta from sticking to each other.
Make the meat sauce. Brown the ground beef and Italian sausage in a Dutch oven until no longer pink, along with the chopped onion and minced garlic. Drain the excess fat.
Mix in the crushed tomatoes, tomato sauce, Italian seasoning, red pepper flakes, ground cinnamon, salt, and pepper. Simmer for 15-20 minutes. Preheat the oven to 350 F.
In a large mixing bowl combine the ricotta, Parmesan, one cup of shredded mozzarella, egg, and chopped parsley until combined.
Stir in the cooked pasta.
Spoon one-third of the meat sauce into a 9x13-inch casserole dish.
Add half of the pasta and cheese mixture.
Sprinkle ½ cup shredded mozzarella over the pasta.
Repeat the process ending with the final ⅓ meat sauce and ½ cup of shredded mozzarella.
Bake for 20 minutes or until the cheese is melted.