01 - Preheat oven to 375°F (190°C). Grease a 9-inch springform pan with olive oil and line the bottom 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, toss with 1 tablespoon olive oil, and set aside.
03 - Heat 2 tablespoons olive oil in a saucepan over medium heat. Sauté onion until translucent, 3 to 4 minutes, then add garlic and cook 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 desired.
04 - In a bowl, blend ricotta, 1 cup mozzarella, Parmesan, egg, parsley, salt, and pepper until smooth and well combined.
05 - Stand drained rigatoni noodles upright in the prepared pan, packing tightly. Using a piping bag or small spoon, fill each tube with the ricotta mixture.
06 - Evenly pour tomato sauce over the stuffed pasta, ensuring it seeps through the noodles. Sprinkle the remaining mozzarella over the surface.
07 - Cover loosely with foil and bake for 30 minutes. Remove foil and continue baking for 15 minutes until cheese is golden and bubbling.
08 - Allow to rest for 10 minutes before releasing springform ring. Garnish with extra parsley and grated Parmesan. Slice and serve.