West Lake Beef Soup

This soup purports to celebrate the picturesque and most famous lake in China, the West Lake, not too far away from Shanghai. To be absolutely correct, a small amount of only the leaves of watercress should float on the soup’s misty surface, which is caused by the use of egg white. But I have used the stalk of the watercress as well because I don’t see any point in wasting such a precious and delicious vegetable. If there is no watercress, just use some individual leaves of cilantro, good f