Preheat oven to 190°C/gas mark 6.
1) Heat the olive oil in a large oven proof saute pan over medium heat, add the onions and garlic and cook for about 5 minutes until translucent. Add the red pepper flakes and dried oregano and cook for 1 minute more. Add the vodka and continue cooking until the mixture is reduced by half.
2) Drain the tomatoes through a sieve and crush them into the pan with your hands. Add 2 teaspoons salt and a pinch of black pepper. Cover the pan with a tight fitting lid and place it in the oven for 1 1/2 hours. Remove the pan from the oven and let cool for 15 minutes.
3) Bring a large pot of salted water to a boil and cook the pasta al dente. Drain and set aside.
4) Place the tomato mixture in a blender and puree in batches until the sauce is a smooth consistency. Return to the pan.
5) Reheat the sauce, add 2 tablespoons fresh oregano and enough double cream to make the sauce a creamy consistency. Add salt and pepper, to taste, and simmer for 10 minutes. Toss the pasta into the sauce and cook for 2 minutes more. Stir in 70g Parmesan. Serve with an additional sprinkle of Parmesan and a sprinkle of fresh oregano on each plate.