Mix the meat pieces thoroughly with the grated onion, sumac, nutmeg, lime juice, dried lime powder, oil, salt, cumin, cinnamon, and turmeric, and let it marinate in the fridge overnight, or at least 3-4 hours. Mix the rosewater with ground saffron.

After draining the rice, layer the marinated meat over the rice and sprinkle a little of the rosewater-saffron mixture over each layer, then let it steam over low heat. The steaming time is longer than for regular rice, since the best part of this dish is the crust (tahdig) — the longer it steams, the thicker the crust.