Roast the whole spices in little oil until it starts changing color. Add shallots, curry leaves and red chilli. fry for a minute. Put in all the powders (sambar, coriander, turmeric and chilli powder). Mix well and fry for a minute in simmer. Put off stove and grind it to a smooth paste
Heat oil in a cooker, splutter mustard seeds, Fry chopped onions and green chilli until onions turn pink.
Add chopped garlic to it and fry for half a minute. Goes in chopped tomato. Saute again for a minute on medium flame. Drop in the cleaned banana flowers (soaked in buttermilk)
Add the ground masala to this, Pour in tamarind water, coconut milk, Salt required and Pressure cook for 3 whistles.