01 - Preheat oven to 375°F. Grease a 9-inch springform pan with olive oil and line the base with parchment paper.
02 - Bring a large pot of salted water to a boil. Add rigatoni and cook until very al dente, about 2 minutes less than package instructions. Drain, toss with 1 tablespoon olive oil, and set aside.
03 - Heat 2 tablespoons olive oil in a saucepan over medium heat. Sauté the onion 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 for 15 to 20 minutes, stirring occasionally. Adjust seasoning as needed.
04 - In a mixing bowl, blend ricotta, 1 cup mozzarella, Parmesan, egg, parsley, salt, and pepper until smooth.
05 - Set rigatoni upright, tightly packed, in the prepared pan. Using a piping bag or small spoon, fill each pasta tube with the ricotta mixture.
06 - Pour the tomato sauce evenly over the filled rigatoni, allowing it to seep between the noodles. Sprinkle the remaining mozzarella across the top. Cover loosely with foil and bake for 30 minutes. Remove foil and continue baking 15 minutes, until the cheese is golden and bubbling.
07 - Let the cake rest for 10 minutes before releasing the pan. Garnish with extra parsley and grated Parmesan. Slice and serve warm.