Cream of Watercress Soup

Our leftover watercress ended up in this soup which we had for dinner tonight. I wanted to follow this recipe I found on the Internet, but I must confess that I did not pay any attention to quantities. (I am quite spontaneous when I cook, except when I am baking.) Watercress and waxy potatoes paired well and produced a delicate, beautiful colored soup. The only point to note is to add the watercress at the end and to cook it shortly so that the color of the soup remains a bright green.