1. In a mixing bowl, add 1 kg mutton cut into curry pieces, 2 tbsp ginger garlic paste and keep it aside to marinate for 1 hour.
2. In a bowl, soak 20 mathania chillies in water for sometime. then grind into a fine paste. keep aside.
3. In a large saucepan, heat 1/4 cup ghee and splutter 10 black peppercorns, 2 green cardamom, 1 black cardamom and saute well.
4. Add 250 gms sliced onions and saute till translucent. add the marinated mutton and saute for 4-5 minutes.
5. Add salt to taste, the ground mathania chilli paste and saute well for 4-5 minutes to remove rawness of chillies. cover and let it cook for 30 minutes.
6. Add in 1.5 tbsp red chilli powder, 1/2 tbsp coriander powder, and 2 tbsp mustard oil in 200 gms beaten curd and mix. cook until mutton becomes tender. serve with roti.