Wash and clean Brussels sprouts. Skin the onion and dice it very finely, sauté in olive oil until translucent. Stir in the curry and immediately add the chopped Brussels sprouts. Pour in the chicken stock and coconut milk and simmer gently until the Brussels sprouts are cooked through. Take some of the Brussels sprouts out of the soup and puree the rest. Season with lime juice, salt and pepper and add the Brussels sprouts again. Decorate with the chopped coriander and the previously fried king prawns and serve.