01 - Preheat oven to 375°F. Lightly 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. Boil rigatoni until very al dente, about 2 minutes less than package instructions. Drain and toss with 1 tablespoon olive oil. Set aside.
03 - In a saucepan, heat 2 tablespoons olive oil over medium heat. Add chopped onion and sauté until translucent, about 3 to 4 minutes. Stir in garlic and cook for an additional minute. Add crushed tomatoes, tomato paste, oregano, basil, sugar, salt, and pepper. Simmer for 15 to 20 minutes, stirring occasionally. Adjust seasoning to taste.
04 - In a mixing bowl, combine ricotta cheese, 1 cup of mozzarella, Parmesan, egg, parsley, salt, and pepper. Mix until smooth and evenly incorporated.
05 - Stand rigatoni upright, tightly packed, in the prepared pan. Fill each tube with the ricotta mixture using a piping bag or small spoon.
06 - Pour tomato sauce evenly over the filled pasta, allowing it to seep between the noodles. Sprinkle the remaining mozzarella evenly on top.
07 - Cover loosely with foil and bake for 30 minutes. Remove foil and bake another 15 minutes, until the cheese is golden and bubbling.
08 - Let the cake rest for 10 minutes. Release the springform pan, garnish with extra parsley and Parmesan, then slice and serve.