01 - Preheat oven to 375°F (190°C). Lightly grease a 9-inch springform pan with olive oil and line the base with parchment paper.
02 - Boil the rigatoni in a large pot of salted water until just very al dente, about 2 minutes less than package directions. Drain and toss with 1 tablespoon olive oil to prevent sticking.
03 - Heat 2 tablespoons olive oil in a saucepan over medium heat. Add onion; sauté until translucent, 3 to 4 minutes. Stir in garlic and cook for 1 minute. Add crushed tomatoes, tomato paste, oregano, basil, sugar, salt, and pepper. Simmer uncovered for 15–20 minutes, stirring occasionally. Adjust seasoning if needed.
04 - Combine ricotta, 1 cup mozzarella, Parmesan, egg, parsley, salt, and black pepper in a mixing bowl. Stir until smooth and well distributed.
05 - Pack the rigatoni upright, side by side, into the prepared pan. Use a piping bag or spoon to fill each pasta tube with the ricotta mixture.
06 - Spread the tomato sauce evenly over the filled pasta, allowing it to seep between noodles. Sprinkle the remaining mozzarella cheese uniformly over the top.
07 - Cover loosely with foil and bake for 30 minutes. Remove foil and continue baking for an additional 15 minutes until golden and bubbly on top.
08 - Allow the dish to rest for 10 minutes before releasing the springform pan. Garnish with extra parsley and Parmesan. Slice and serve.