Yoghurt with Cucumber

This dish does of course crop up in the cuisine of every country east of Athens and west of Tokyo (think of the Greek tsatsiski, or the Indian raitha), but that does not make it any the less authentic with Persian food. In Iran they benefit from having the weensiest cucumbers with the most wonderful fresh flavour – gorgeous to eat on their own with a sprinkling of salt: these are available in England in Middle Eastern shops, but a run-of-the-mill cucumber will do. A proper Ira