Mix mutton pieces, ginger-garlic paste, red chilli powder, coriander powder, turmeric powder, cumin powder, garam masala powder, two cups of water and salt in a pressure cooker. Mix well and bring mixture to a boil on high heat. Cover and cook under pressure till four to five whistles are given out or till the mutton is cooked.

Open the pressure cooker when the pressure reduces completely and continue to cook till the mutton mixture becomes dry

Heat oil in a non-stick pan. Add onion and sauté till golden. Add tomato and green chillies, mix well and cook till tomato becomes pulpy.

Halve naan horizontally. Heat some butter in another non-stick pan and toast the naan halves.

Add potato to the onion-tomato mixture, mix well and sauté for a minute.

Add mutton mixture, mix well and sauté for a couple of minutes. Add half cup of water, mix well and cook for three to five minutes

Place a generous portion of the cooked mutton mixture on the bottom half of the toasted naan.

Roughly chop some mint and coriander leaves and sprinkle on top. Cover with the top half of the naan and place the sandwich back on a hot tawa.

Apply butter on top of the sandwiches and cook for two to three minutes on each side

Cut into wedges, arrange on a serving plate and serve hot.