01 -  Preheat oven to 375°F. Grease a 9-inch springform pan with olive oil and line the base with parchment paper. 
 02 -  Cook rigatoni in a large pot of salted boiling water until very al dente, about 2 minutes less than package instructions. Drain and toss with 1 tablespoon olive oil. Set aside. 
 03 -  Heat 2 tablespoons olive oil in a saucepan over medium heat. Add chopped onion and sauté until translucent, about 3 to 4 minutes. Stir in minced 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 if needed. 
 04 -  In a mixing bowl, combine ricotta cheese, 1 cup mozzarella, Parmesan, egg, parsley, salt, and pepper. Mix until fully blended and smooth. 
 05 -  Stand rigatoni noodles upright and tightly packed in the prepared pan. Using a piping bag or small spoon, fill each tube with the ricotta mixture. 
 06 -  Pour tomato sauce evenly over the filled pasta, letting it seep between the noodles. Sprinkle the remaining mozzarella over the top. 
 07 -  Cover loosely with foil and bake for 30 minutes. Remove foil and continue baking for an additional 15 minutes, until cheese is golden and bubbling. 
 08 -  Let stand for 10 minutes before releasing the springform pan. Garnish with additional parsley and Parmesan. Slice and serve.