Heat oven to 180C. Spread walnuts out on a baking sheet and toast until golden brown inside, about 12 minutes. Set aside to cool to room temperature. A small portion of these will be used for the yogurt dip later. They should be roughly chopped and added at the last minute to the dip.
Remove chicken skin and discard or save for another use. In a large bowl, season the chicken with turmeric, two teaspoons salt and half a teaspoon of pepper. Set aside in the refrigerator.
Set a large Dutch oven or similar heavy pot over medium-high heat. When the pot is hot, add oil and carefully lay chicken thighs into the pot in a single layer. It is crucial to leave space between the pieces to allow steam to escape, so brown chicken in batches if necessary. Cook until browned on both sides, flipping halfway through, three to four minutes per side. Remove chicken from pot and set aside. Put the pot on low heat and add the onion to pot with a pinch of salt and cook, stirring regularly, until soft and golden brown, 16-18 minutes. The onions should be closer to caramelised that crispy.
In a food processor, grind the cooled walnuts as finely as possible without turning them into a paste. (Alternatively, you can chop the walnuts as finely as possible by hand.) Add two cups pomegranate juice and quarter of a cup of molasses to the walnuts and continue blending until you have a very smooth paste.
Add the walnut paste and remaining pomegranate juice to the pot. Season with salt and partly cover with a lid. It should still be very liquid at this point. Cook over low heat, stirring frequently, for about two hours. If the sauce begins to stick or get too thick, stir in quarter of a cup of water. The sauce will thicken and change colour as it cooks, turning a deep, dark brown.
Add the saffron, and taste the sauce. Adjust seasoning with salt, pepper and pomegranate molasses as needed. The sauce should be delightfully sweet and sour, so add up to two teaspoons sugar, if needed, if it's too tart.
Add the chicken to the sauce and simmer, partially covered, for 45 minutes, or until chicken is falling off the bone. Keep stirring regularly – the sauce should be thick, but not so thick that it sticks to the bottom of the pot, so add a splash of water as needed to prevent burning. Use a large spoon to skim away any walnut oil that has pooled on top of the stew. Taste and adjust seasoning, transfer to a serving dish and garnish with a sprinkling of fresh pomegranate seeds. Serve hot, with Persian rice, mast-o khiar and salad-e Shirazi if you like.
For the yogurt dip: https://www.goodfood.com.au/recipes/masto-khiar-persian-cucumber-and-herb-yoghurt-20190617-h1fg6u In a small bowl, submerge the raisins in boiling water to plump for 10 minutes, then drain well.
Remove alternating stripes of peel on cucumbers and trim ends. Dice cucumbers into pieces and place in a large bowl with raisins, yoghurt, fresh herbs, garlic, three-quarters teaspoon salt, half teaspoon pepper and, if using, half the rose petals. Add dried mint and dried dill into the bowl. Stir to combine and adjust seasoning with salt as needed.
Just before serving, stir in the walnuts and transfer to serving bowl. Garnish with remaining rose petals, if using. Cover and refrigerate leftovers for up to three days.