Jerusalem artichoke (wut?)

It seems that what we call "Aardpeer" is called "Jerusalem artichoke" in English. At least, that's what happens when I change the wikipedia-page's language ;)

Any native speakers know if this is a common word, or should I be using the alternatives given (sunroot, sunchoke, earth apple or topinambour). Earth apple is close to the dutch name ('earth pear").

Anyway, this is for my sister who dispairs when she gets them. What to do with those? Well, this. Recipe should be obvious from the shot, duh :P