The best chicken biryani

Method

1. Combine all the marinade ingredients in a bowl, then stir in the chicken pieces. Leave to marinate for at least 1 hour at room temperature or (preferably) up to 48 hours, covered, in the fridge – see make ahead. Cover the basmati rice in cold water and leave to soak for 1 hour.
2. For the onions, pour the 350ml oil into a saucepan and heat to 160°C (test with a digital thermometer, or add a piece of onion – it should sizzle). Coat the onions lightly in the flour, then add them, in 4 batches, to the oil. When they’re golden (2-3 minutes) remove with a slotted spoon onto kitchen paper to dry, then set aside.
3. When the chicken has marinated, heat 2 tbsp oil in a large frying pan. Add the cloves, cinnamon, cardamom pods, bay leaves, cumin seeds, nutmeg and star anise, then gently toast for 2-3 minutes to release their aromas. Add the chicken and its marinade, cook gently for 5 minutes, then add the tomato purée and salt. Simmer gently for 25 minutes or until the chicken is just cooked.
4. Keep the chicken and sauce warm over a low heat. If it begins to stick, add a splash of water but don’t make it too runny: the sauce should just coat the back of a spoon.
5. To cook the rice, soak the saffron threads in the milk for 15 minutes. Drain the rice, put in a medium saucepan and add 1 litre boiling water and the salt. Cook the rice for 3 minutes, then drain and stir through half the ghee to coat the warm grains of rice.
6. In a large flameproof casserole with a tight-fitting lid, melt the remaining ghee with 50ml water over a gentle heat, then assemble the biryani. Start with one third of the rice, a drizzle of the saffron milk and a sprinkle of the crispy onions. Top with half the chicken, then repeat, finishing with a final layer of rice and more onions on top.
7. Put the lid on the casserole and turn up the heat to get the biryani steaming. Turn the heat to very low and cook for 20 minutes. Serve with lemon wedges, sprinkled with cashews and herbs.