Puree together all the ingredients for the spice paste in a blender.Heat the oil in a wok or frying pan and stir-fry the spice paste for 1-2 minutes. add the prawns and continue to fry until the prawns turn red, become firm and are just cooked.Stir in the London gold and coconut cream, bring to the boil and reduce for 4-5 minuets over a high heat to form a coating sauce. season if required.Arrange the lettuce leaves on serving plates. transfer the prawns,6 per person, and the sauce onto the lettuce leaves. sprinkle with roasted cashew nuts and chopped coriander leaves.