Wash and clean mutton pieces. Drain out water completely.
Marinate mutton pieces with ginger - garlic paste, turmeric powder, whisked yogurt and salt.
Cover and keep aside for half an hour.
For the masala:
Dilute red chilli powder, turmeric powder and coriander powder in 2 tbsp water (spice mix). Keep aside.
In a pan, heat oil or ghee and add whole spices (bay leaf, cloves, cardamoms and cinnamon stick).
Fry on low heat until fragrant.
Add sliced onions and fry till golden colour on low to medium heat.
Add slit green chilli and stir well.
Add ginger - garlic paste and stir well for 2 - 3 minutes or until the raw smell goes.
Add diluted spice mix (red chilli powder - turmeric powder - coriander powder) and stir well on low heat for 2 - 3 minutes or until well blended and water dries up.
Add sliced tomatoes.
Stir well for 4 - 5 minutes or until the tomatoes are well mixed with onions and other spices / tomato gravy thickens.
Add chopped mint and coriander leaves. Mix well.
At this point, add marinated mutton pieces (along with thick yogurt / curd) and salt to taste. Cover with a tight lid and cook on a low to medium heat for 40 - 50 minutes or until mutton pieces softens and gravy thickens ( you may get approximately 3/4 - 1 cup thick gravy).
For the rice:
In a pan, heat ghee. Add peppercorns, fennel seeds, cardamom and cloves and fry till fragrant.
Put all the fried spices, salt and ghee in water and boil. Add rice, and cook until 3/4th done (do not overcook rice. Each rice grain should be separated).
Remove whole spices when assembling.
Heat oil / ghee in a pan and add sliced onions and fry until golden brown and crisp on medium to low heat. Keep aside.
Add cashew nut splits and fry on low heat until golden colour. Keep aside.
Add raisins and fry on a low heat until golden colour. Keep aside.
In a heavy - bottomed vessel or biryani pot or thick non-stick kadai, spread a layer of lamb (mutton) masala (along with half portion of thick gravy) and half portion of cooked rice.
Make 2 layers with cooked rice and mutton masala. Sprinkle 1 tbsp ghee, golden onions, saffron solution (optional), chopped coriander - mint leaves and shallow fried raisins and cashew nuts.
Gently put a wet soft towel over it. It will help to 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 and cook on a low heat for 30 minutes.
You can find a colour change on the maida seal. Switch off the heat and keep aside for another 15 minutes.
Open the seal carefully.
Decorate with chopped coriander and mint leaves. Serve hot with raita, pickle, boiled egg.