Place potatoes in a saucepan with 2 tsp salt and cover with water. Bring to the boil, then reduce heat to medium and cook for 45 minutes or until tender. Meanwhile, place chicken in a large saucepan with onion, garlic, 2.5 litres water and 2 tsp salt. Bring to the boil, skimming any impurities that rise to the surface. Reduce heat to medium and cook for 45 minutes or until chicken is cooked through.
Drain potatoes. When cool enough to handle, peel potatoes and cut into 2 cm-thick batons.
Transfer chicken to a plate, reserving 60 ml strained cooking liquid. When cool enough to handle, remove and discard skin and bones, then thickly slice meat and set aside.
To make dressing, whisk together all ingredients with reserved cooking liquid. Season with salt and pepper. Set aside.
Arrange potatoes, chicken, eggs, carrot, peas, olives, grapes and pickles on a plate. Serve with dressing and flatbread.
* Sour grapes are available in jars from Persian food shops.
As seen in Feast Magazine, Issue 13, pg80.
Photography by John Laurie