Heat 4 1/2 cups water in a heavy bottomed vessel or non-stick pan.
Add bay leaves, cloves, cardamoms, cinnamon, star anise, ghee and salt.
When the water boils completely, add rice.
Cover with a tight lid and cook on a low heat for 15 - 18 minutes or until the water completely dries up.
Each grain of rice should be separated. Keep aside.
For fried onion - cashew nuts and raisins:
Heat oil in a pan. Add finely sliced onions and fry on a low to medium heat until golden colour and crisp.
Do not fry on high heat. Approximate frying time is 15 - 18 minutes. Drain out oil and keep aside.
Add cashew nuts and fry on a low heat until golden colour.
Add raisins and fry on a low heat until golden colour. Keep aside. Do not use remaining oil.
For the chicken masala:
Finely crush slit green chillies, garlic and ginger. No need to make fine paste in a mixer / blender (or you can use mortar and pestle). Keep aside.
Heat oil in a pan. Add finely sliced onions and fry medium golden colour.
Add crushed ginger - garlic and green chilli mixture. Stir well on a low to medium heat until light brown.
Add chopped tomato and chopped coriander - mint leaves. Stir well for 5 - 8 minutes.
Add chicken pieces and salt to taste. Mix well.
Add lemon juice. Stir well continuously on a low heat for 2 - 3 minutes.
Add garam masala powder. Cover with a tight lid and cook on a low heat for 25 - 35 minutes or until done and the gravy thickens. Do not add water when cooking.
For the dum:
In a heavy - bottomed vessel or biryani pot, spread a layer of chicken masala (along with thick gravy) and half portion of cooked rice.
Make 2 layers with cooked rice and chicken masala.
Sprinkle 1 tbsp ghee, chopped mint and coriander leaves, fried onions, cashew nuts and raisins (1 tsp diluted saffron and 1 tsp rose water, optional).
Carefully place a wet towel over it. It will retain the flavour of the biryani.
Cover with a tight lid. Seal with maida dough on the edges of the lid.
Heat a heavy - bottomed iron kadai. Keep biryani pot over it. Cook on a low heat for 25 - 30 minutes. You can find a colour change on the maida seal. Open the seal carefully. Serve with raita / pickle / boiled egg / pappadam.