Heat a pan adding oil, mustard seeds, lentils and curry leaves. When mustard splutters, include chopped onion and saute till translucent. Add green chillies and turmeric powder.
Next include cooked and mashed potato and salt. Mix everything well. Finally add coriander leaves and squeeze some lemon. Stuffing is ready. Next slit the bajji chillies and remove all seeds.
Next in a bowl, add gram flour. rice flour, salt and red chilly powder. Give a quick mix.
Include water little by little and prepare slightly thicker batter. The consistency should be like dosa batter. Meanwhile heat some oil in a heavy bottom pan.
Next, take the slit chillies and fill with potato stuffing. Keep the chillies ready for deep frying. Dip a stuffed chilly in gram flour batter and carefully drop in to hot oil.
Deep fry the chillies till they turn golden brown and drain over a kitchen tissue.
Very tempting stuffed mirchi bajji is ready to serve with hot tea and coffee.