In a bowl take all the flours ,salt ,hing powder (asf powder)mix well now add water and make into watery mix in such a way to pour as dosa keep aside
Now heat a pan put some oil put mustard, dals, onion, curry leaves and chilli. Fry till the dal turns golden brown put this into the batter mixed
Now keep the dosa pan heat it apply oil then pour into thin dosa put oil around the edges allow to cook till its crispy in low flame ,then take and serve with your favourite chutney.