Grind together ginger, garlic and green chillies into a coarse paste.
Clean and soak rice for 30 mins. Keep aside.
Heat oil in a heavy bottom pan or a kadai.
Add 1/2 of the sliced onions and fry, till golden brown. Keep aside.
Heat up the remaining oil.
Add rest of the sliced onions and cashews and fry, till it becomes soft.
Add tomatoes, ground paste, turmeric powder, pepper powder, curd, mint and coriander leaves and saute, till the oil starts to separate.
Add mutton and cook, till the mutton is 3/4th cooked.
Cook the rice along with all spices and salt, till it is 3/4th done.
Grease a vessel with little ghee.
Spread 1/2 of the mutton masala and place 1/2 of rice over it.
Pour 2 tbspn of ghee on top of it and sprinkle some roasted onion.
Spread the remaining masala and top it with rice followed by ghee and fried onion.
Close it with a air tight lid and put Mutton biryani in dum for 10 - 15 mins.
:- We can put Mutton biryani in oven after layering it in a pyrex or oven safe bowl. Pre heat the oven for 200 degree and keep it for 10 mins.:- If using microwave, layer Mutton Biryani in a microwave safe container and keep the power in defrost mode and set 10 mins.
:- Serve mutton biryani hot with raita and papad.