Pok choi, bok choy, bak choi, pak choi.... I have come to the conclusion they may actually all be the same thing! I used to think that bok choi was the small version, and pok choi was the fully grown vegetable - but after a somewhat confusing trip to the greengrocers yesterday I have reconsidered! It looks like a cross between celery and spinach - though is actually from the cabbage family. If anyone can shed any light on the matter, please do!
What ever it's called, I used the fully grown version for this duck dish - and it tasted great.