Walnut

Juglans regia · charmaghz · akhrot · gerdu

Four kernels in one shell, which is what its Dari name means.

What it is

The walnut is the seed of Juglans regia, the Persian or English walnut: a wrinkled kernel in four lobes inside a hard shell, rich in oil, with a papery brown skin that carries a faint bitterness. Fresh walnuts are sweet and milky; old ones turn rancid and sharp, and in a recipe that uses them raw the difference shows.

Where it comes from

The tree is native from the Caucasus across Iran and Central Asia to the Himalaya, and wild walnut forests still stand in the mountains of Kyrgyzstan. Afghanistan grows walnuts in its eastern and northern valleys, and they are sold in the shell in every bazaar.

What it's called

Charmaghz (Dari, four kernels) · akhrot (Urdu and Hindi) · gerdu (Persian) · Persian or English walnut. The American black walnut is a different tree with a stronger taste.

In the kitchen

Here the walnut goes into both sweet and savoury food. It is eaten with kishmish panir, fresh cheese and raisins, on a summer afternoon; chopped into sheer pira, the milk fudge; soaked and skinned for haft mewa; and ground very fine and boiled into chai-e-zanjafeel, where it clouds the tea. In samanak, whole walnuts in their shells go into the pot, and each stirrer listens for them knocking against the ladle.

What we know about the claims

Walnuts are unusually high in alpha-linolenic acid, the plant omega-3, and trials link eating them regularly with modest improvements in cholesterol. They are also dense in calories, which nobody eating sheer pira will be surprised by.

Choosing and buying

Buy them in the shell, or from a shop with a fast turnover, and taste one: a fresh walnut is sweet, a stale one bitter and paint-like. Afghan and Iranian grocers sell good kernels by weight. Keep shelled walnuts in the fridge or freezer. For haft mewa, pour boiling water over them and the skins rub off.