1. Heat oil, saute onions until slightly browned. Add tomatoes along with onions(if you are adding it). Then add urad dhal and sate till golden brown.
2. Then add tamarind, red chilli saute for a minute. Then add coconut, salt, hing and saute till golden brown. Then add coriander leaves and switch off. Give a stir once and set aside to cool. Add little water and then grind it to semi coarse mixture with little
You can even skip coconut and add in more coriander leaves.
Adding tomatoes gives a nice flavour.
No need to saute more after coriander leaves is added, let it shrink in the switched off heat itself.