In grammar school mathematics you learn early on that a negative plus a negative is more negative, but a negative times a negative equals a positive…it’s all very confusing when you’re nine, especially because in real life when do you ever see a negative and a negative becoming anything besides EXTRA NEGATIVE? I’m not sure that this analogy exactly translates to this recipe (am I really multiplying ingredients?) but all I know is that celery has a terrible texture, celery root has a look (and frankly taste) only its mother could love, but when you combine them together in this soup, magic happens, the angels sing and it’s the best soup you’ve eaten in a long time.