Peel the onions. Roughly chop two of them and thinly slice the others. Warm the olive oil in a large pan set over a moderate heat, add the two chopped onions and fry them for ten to fifteen minutes till soft and pale gold. Peel and thinly slice the garlic, then stir in with the ground turmeric and continue cooking for a couple of minutes.

Drain the chickpeas and haricots and stir into the onions together with the lentils and stock. Bring to the boil, then lower the heat and leave to simmer for 30 minutes, stirring occasionally.

Melt the butter in a shallow pan, then add the reserved sliced onions and let them cook slowly, with the occasional stir, until they are a rich toffee brown. This will take a good half an hour, maybe longer.

Add the noodles to the simmering beans. Wash the spinach, put it in a pan set over a medium heat, cover with a lid and leave it for three or four minutes until it has wilted. Turn occasionally with kitchen tongs. Remove the spinach and put it in a colander under cold running water until cool. Wring the moisture from the spinach with your hands, then stir into the simmering stew. Roughly chop the parsley, coriander and mint leaves and stir most of them into the onions and beans.

Fold in the soured cream, then ladle into bowls and fold in the remaining herbs and the fried onions.

One of the dishes we ate time and again when in Iran, this is a bowl of deep, wholesome goodness. The soup is soothing and sustaining and was much appreciated by our film crew after a long, dusty day’s work.

Traditionally you would use the flat reshteh noodles, but any will work, even small round pasta if you prefer. Gently stir all the ingredients together at the table to produce a silky textured soup-stew.

From Greenfeast: Autumn, Winter, by Nigel Slater, published by 4th Estate Books. Photographs: Jonathan Lovekin