1. Place chicken pieces, yoghurt and first five spices in a bowl and leave to marinade for at least 30 minutes.
2. Heat half the oil in a large frying pan, fry almonds until golden, drain. Fry sultanas a few seconds, drain and set aside. Fry potato halves until brown, drain and reserve.
3. In a large saucepan, heat rest of the oil and fry onion, garlic and ginger until onion is golden. Add both chillies and chilli powder, pepper, turmeric, cumin, salt and tomato. Stirring continuously, fry for 5 to 6 minutes. Add yoghurt, mint, cardamom and cinnamon. Cover and cook over a low heat until tomato is cooked to a pulp. (If the mixture becomes too dry and starts sticking, add a little hot water to pan).
4. Drain chicken pieces and add to spice mixture, cover and continue cooking over a low heat until chicken is tender (35 to 45 minutes). There should be only a very little thick gravy left when the chicken is cooked. If not, cook uncovered to reduce gravy.
5. BIRIANI RICE: Wash rice well and drain in colander for at least 30 minutes. Heat oil and fry onion until golden, add turmeric, cloves, salt and black pepper. Fry stirring, until rice is covered with oil. Pour stock over rice mixture and stir well.
6. Add chicken mixture and potatoes to rice mixture, mix gently together. Bring to boil, cover tightly with lid and turn heat down to very low and steam for 20 minutes. DO NOT lift lid during cooking.
7. TO SERVE: Spoon biriani onto a warm dish, garnish with almonds, sultanas and dhania leaves. Absolutely delicious with a cucumber raita, onion sambal and hot pickles on the side.