I found this recipe on a Belgian website while I was looking to emulate my (Belgian) boyfriend's father's chervil soup. This soup came out lighter in color than his, more of a creamy green as opposed to dark green, but it is simple and delicate. I have a sneaking suspicion that he doesn't use leeks in his, but I think the leeks add a fuller dimension that I found really satisfying. We eat soup every day of the week with dinner, so it always gets made in big batches and served all week long. Light soups like this are nice for spring. Add little soup meatballs if you like (I do). Also, I used 2 leeks instead of 3 by accident and used a little more water than called for, and it still tasted really nice. I guess the most important thing is not to cook this soup too long because the delicate flavors will deteriorate if overdone.