Avocado and Watercress Soup

Until recently avocado hadn’t been much used in Asian cooking. When ‘East meets West’ became fashionable 20-odd years ago, though, and more and more people were introduced to guacamole, avocado started to penetrate into middle-class homes via international hotel restaurants. Don’t add cream or yoghurt to the blended soup, as they will make the colour too pale.