01 - Preheat the oven to 375°F. Grease a 9-inch springform pan with olive oil and line the base with parchment paper.
02 - Boil rigatoni pasta in a large pot of salted water until very al dente, about 2 minutes less than package directions. Drain and toss with 1 tablespoon olive oil. Set aside.
03 - Heat olive oil in a saucepan over medium heat. Sauté onion until translucent, 3 to 4 minutes. Add garlic and cook for 1 minute. Stir in crushed tomatoes, tomato paste, oregano, basil, sugar, salt, and pepper. Simmer for 15 to 20 minutes, stirring occasionally. Adjust seasoning if needed.
04 - Mix ricotta, 1 cup mozzarella, Parmesan, egg, fresh parsley, salt, and pepper in a bowl until smooth.
05 - Arrange rigatoni upright, tightly packed, in the prepared pan. Fill each pasta tube with the ricotta mixture using a piping bag or small spoon.
06 - Pour tomato sauce evenly over the filled pasta, allowing it to penetrate between noodles. Sprinkle the remaining mozzarella on top.
07 - Cover with foil and bake for 30 minutes. Remove foil and bake for 15 minutes more, until the cheese is golden and bubbling.
08 - Allow to cool for 10 minutes before releasing the springform pan. Garnish with fresh parsley and extra Parmesan. Slice and serve.