Fesenjan (Walnut and Pomegranate Stew)

Variations

• It thickens with neither starch nor roux. Thickening a sauce lists three methods — starch, roux and reduction — and adds collagen as "the fourth method". Fesenjan is a fifth that is not on that list: finely ground nuts. Over a long simmer the walnuts' cell walls break down, their oil and fine particles disperse through the liquid and emulsify, and that is the body. Which is why how finely you grind them is part of the recipe rather than a preference.
• The sign that it is done is also different. When oil rises on a curry, that is added fat separating. What rises here is the walnuts' own oil — which is the evidence that the nuts have broken down completely.
• Pomegranate molasses does a different job here than elsewhere on this site. In baba ganoush, fattoush, tabbouleh and kibbeh it is a dressing spooned over at the end; in fesenjan it goes in as the backbone of the sauce. Buy the sour, unsweetened kind — it is better to add the sweetness yourself.
• North and south disagree. Gilan and Mazandaran barely sweeten it and it comes out frankly sour; Tehran and the south take it sweeter. Neither is the correct one.
• Meat: chicken thigh is the everyday version and duck is the grandest. Small meatballs are common, and a vegetarian version uses squash or aubergine.
• With ghormeh sabzi it makes the two poles of Iranian khoresh. That one fries herbs for twenty-five minutes, this one simmers nuts for two hours — both take one ingredient and work it long enough to change the whole pot.
• Against the peanut sauce in satay: both grind nuts into a sauce, but that one is simmered briefly with coconut milk and keeps its grain, while this is cooked until no grain is left at all.

Tips

• Do not scorch the walnuts. The light toasting is for aroma, not colour. Once they start to brown it is already too late, and nothing added later covers that bitterness. If in doubt, skip the toasting and use them raw.
• Grind them fine. Finer than that. This is what most often goes wrong. Do not pulse a few times and stop — scrape the sides down and keep going until it is a paste.
• Stir every ten minutes. Ground walnut is heavy, it settles, and what settles scorches. A thick-based pot helps a great deal.
• Keep the heat low. At a hard boil the walnut oil separates out early and the sauce splits. Aim for a surface that barely moves.
• Pomegranate molasses goes in partway, not at the start. Three hours of reducing makes the sourness sharp and the colour muddy.
• Balance the sweetness at the end. Brands differ enormously in sourness, so the sugar quantity is a starting point. Add a tablespoon at a time and taste.
• If it is thin, simmer it uncovered. Do not add starch — the moment you do it stops being this dish.
• It is better the next day, once the walnut oil and the pomegranate settle. Plenty of Iranian households make it a day ahead.
• Serve it with plain white rice. It is rich, sour and sweet all at once, and it needs something that tastes of nothing beside it.