firstly for making gothsu powder, dry roast coriander seeds, chana dal and red chillies until it is slightly reddish. cool and grind to fine powder.
heat oil in same pan, fry onions, potatoes and brinjal until roasted. cool and grind coarsely
heat oil again in same pan and pop in mustard seeds, urad dal, chana dal, curry leaves, green chilli chopped and chopped onions.
fry until onions are slightly brown. further add tamarind water and let it come to a rolling boil.
when it is boiling, add gothsu powder, ground potato brinjal paste and mix well
add a pinch of asafoetida, water, drizzle some oil over it, close and cook for 5-10 minutes until oil leaves the sides.
open and mix again. serve with idli/dosa/pongal.