Place the vegetable stock, white wine and saffron in a saucepan and bring to the boil. Add the cod and cook gently for 2-3 minutes or until just cooked. Remove the cod with a slotted spoon and set aside. Boil the wine and stock rapidly until reduced by about a half. Stir in the cream and simmer for a further 4-5 minutes until thickened. Melt the butter in a large heavy-based frying pan. Add the shallots and garlic and cook gently until softened. Add the courgettes and cook for 2-3 minutes until tender. Gently reheat the saffron sauce, if necessary. Season and add the cod and prawns and heat gently until piping hot. Stir the courgette mixture into the sauce. Meanwhile, cook the pasta as directed on the packet. Drain, place in a heated serving dish and pour the sauce over. Serve with mixed green salad and crusty bread. NOTES : This colourful combination of courgettes, prawns and saffron makes a delicious summery sauce for serving with fresh or dried pasta. We have used tagliatelle in this recipe but fettuccine, linguine, pappardelo or even spaghetti would be equally good.