Preheat the Oven: Initiate by setting the oven temperature to 375 degrees Fahrenheit (190 degrees Celsius). Concurrently, apply a light coating of non-stick cooking spray or butter to a 9x13-inch baking dish to prevent sticking.
Prepare the Pasta: Fill a large pot with water, season with a pinch of salt, and bring to a vigorous boil. Submerge the ziti pasta in the boiling water and cook for approximately 8 to 10 minutes, until it is al dente. Once cooked, drain the pasta and rinse under cold water to halt the cooking process.
Combine Ingredients: In a medium mixing bowl, amalgamate the cooked ziti, ricotta cheese, mozzarella cheese, and the beaten egg with 1 and 1/2 cups of spaghetti sauce. Stir the mixture until each ingredient is evenly distributed throughout.
Assemble the Dish: Transfer the pasta mixture into the prepared baking dish, spreading it out evenly. Layer the remaining spaghetti sauce over the pasta and garnish the surface with the grated Parmesan cheese.
Bake: Place the baking dish in the preheated oven and bake for 30 minutes, or until the top is golden brown and the cheese has melted thoroughly. After baking, remove the dish from the oven and let it rest for 15 minutes to allow the ingredients to settle and the flavors to meld together.