Shell and devain the shrimp. Rinse well and pat dry. Set Aside. Heat the butter in a skillet and add the onion. Add the chili. Cook briefly and add the shrimp, salt and pepper to taste. Cook, stirring often, about three minutes. Add the cardamom and cumin and stir. Add the lime juice, sour cream, and yoghurt. Bring gently to a boil stirring. Sprinkle with coriander and serve hot with saffron rice. ----