Melt butter and saute garlic and chilli flakes (optional) until soft. Add prawns and cook until pink. Remove prawns from heat and set aside. Add wine, tomatoes, seasonings, cream and cheese. Simmer for 10 minutes.
Meanwhile, prepare pasta: bring a large pan of water and the oil to the boil. Add spaghetti and cook until tender but still firm. Drain, rinse under warm water and drain again. Return to pan. Add prawn sauce and toss over low heat for 1-2 minutes. Serve garnished with parsley and extra Parmesan if desired.