Heat the oil in a pan, sauté the garlic and leek for approx. 5 mins., add the tomatoes, bring to the boil, reduce the heat, simmer for approx. 25 mins., season, mix in the pine nuts.
Heat the oil in a non-stick frying pan, add the rosemary. Fry the prawn tails for approx. 6 mins. all over, add salt and serve with the winter salsa.