01 - Preheat oven to 375°F. Grease a 9-inch springform pan with olive oil and line the base with parchment paper.
02 - Boil rigatoni in a large pot of salted water until very al dente, about 2 minutes less than package directions. Drain thoroughly and toss with 1 tablespoon olive oil. Set aside.
03 - Heat 2 tablespoons olive oil in a saucepan over medium heat. Sauté the chopped onion until translucent, 3 to 4 minutes. Add minced garlic and cook for 1 minute. Stir in crushed tomatoes, tomato paste, oregano, basil, sugar, salt, and pepper. Simmer for 15 to 20 minutes, stirring occasionally. Adjust seasoning as needed.
04 - In a mixing bowl, combine ricotta, 1 cup mozzarella, Parmesan, egg, parsley, salt, and black pepper. Mix until thoroughly blended and smooth.
05 - Stand the rigatoni tubes upright, packed tightly, in the prepared pan. Using a piping bag or small spoon, fill each noodle with the ricotta cheese mixture.
06 - Pour tomato sauce evenly over the filled rigatoni, allowing it to seep between the noodles. Scatter the remaining 1 cup mozzarella on top.
07 - Cover the pan loosely with foil and bake for 30 minutes. Uncover and bake for another 15 minutes until the top is golden and bubbling.
08 - Allow the pasta cake to rest for 10 minutes. Release the springform pan, garnish with extra parsley and Parmesan, slice, and serve.