Pistachio nut. The fruits of a small tree which originated in Central Asia, probably eastern Syria, but which is now widely cultivated. Just before harvest pistachios are enclosed in a green and magenta fleshy cover. These are the very best, if you can get them. However, fresh pistachios are rarely seen, mainly because they have a short shelf-life. They are usually hulled and dried, after which they are either roasted or roasted and salted. For cooking use the ones which are not already salted. They are sold in their creamy beige shells, which split as they ripen. The shells should be removed and the purple papery skins rubbed off revealing the bright green kernels within, the greener the better. They are related to both the cashew and the mango.