1. Soak the rice in a bowl of cold water for 30 minutes. Drain and rinse well, then cook the rice in a large pan of boiling, salted water for 7-8 minutes. Drain well.
2. Melt the butter in a medium lidded saucepan. Add the cinnamon stick, lemon zest, pomegranate molasses, raisins and pistachios. Fry for 2 minutes, then remove from the pan with a slotted spoon and reserve.
3. Spoon a thin layer of rice over the bottom of the pan. In a large bowl, toss together the remaining rice, reserved fruits, nuts and spices and the leftover chicken, and season well. Spoon into the pan, then pour over the saffron and its soaking water. Using a chopstick (or similar), make 4-5 holes in the rice. Wrap the pan lid in a clean tea towel and cover the pan. Cook on a low heat for 30 minutes.
4. To serve, spoon out any loose rice onto a serving platter, then immediately plunge the bottom of the pan into a bowl of cold water to loosen the crusty rice layer, which is delicious. Serve this scattered over the loose rice. Top with the yogurt, pine nuts, herbs and fried onions.