Drain roasted capsicums, reserving a teaspoon of the liquid, then cut into strips.
Combine prosciutto, cream, crushed tomatoes, vodka, roasted capsicums with reserved liquid, parsley, garlic powder, sugar, salt, black pepper and chilli flakes in a saucepan. Cover then cook over medium heat, stirring often, until the sauce comes to a boil. Reduce heat then simmer for 30 minutes.
Meanwhile, cook pasta according to packet directions. Drain then transfer to a large serving bowl. Stir cheese into the sauce. Stir sauce into rigatoni then top with peas.