Firstly wash and soak urad dal and rice atleast for 6 hours
Now grind both and mix and keep covered in a bowl for 5 to 6 hours again
Meanwhile wash and soak Arhar dal for half an hour
Now boil dal adding 2 glasses of water, 1.5tsp salt and turmeric powder
After 10 minutes add chopped vegetables and again keep on slow flame to cook for 10 minutes
Now take a pan and heat 2 tsp oil in it
Add half of the mustard seeds,heeng,whole red peppers and curry leaves
Add chopped one onion
Fry well and add chopped tomatoes
Add sambhar masala and red chilli powder in it
Add this mixture in boiled sambhar
Add tamarind pulp
Mix well and cook for 15 minutes on slow flame then turn off the flame
Boil and peel potatoes and mash them
Keep a pan on flame and heat 2tsp oil
Add mustard seeds and curry leaves and red peppers
Add mashed potatoes
Add sambhar masala and mix well
Turn off the flame after 2 minutes
Now add 1/2tsp salt in dosa batter
Grease the tava and spread a laddle full of batter and let it be crispy and golden
Add potatoes masala in it and serve hot with sambhar
