Chicken in pomegranate-walnut sauce (Khoresh fesenjan)

1. Toast the walnuts in a dry frying pan over medium heat for 4-5 minutes until fragrant, leave to cool, then grind them in a food processor until crumbly, almost a paste.

2. Heat the oil in a heavy pan, fry the finely chopped onions for 8-10 minutes until golden brown, then add the turmeric.

3. Add the chicken thigh fillets cut into large pieces and fry until white on all sides.

4. Stir in the ground walnuts, pour in the water, cover and simmer gently for 40 minutes, stirring often as walnuts burn easily; in this time the walnuts release their oil and the sauce darkens.

5. Stir in the pomegranate molasses, cinnamon, the saffron soaked in a little warm water and the salt, then cook uncovered for another 20-30 minutes until the sauce is thick and dark chocolate brown; balance the sourness with sugar to taste.

6. Serve with plain saffron basmati rice (chelow).

Tip: Fesenjan is one of the jewels of the Persian festive table: a deep, sweet-and-sour sauce. Taste it at the end - if it is too sour, add a little sugar or honey; if too sweet, another spoonful of pomegranate molasses. The slower you cook it, the darker and silkier it becomes.