The leaves of some amaranth species, cooked as a dry curry, are damn tasty. Can't remember where and when I had it, except that it was long ago, and in India. Probably was made with some onions and common Indian spices, but that alone did not account for the good taste - it's the plant itself. Might have been in North or South India - the Wikipedia article says it is used in both those areas, and also many other areas worldwide.