firstly, in a small pan heat 2 tsp oil and saute 1 tsp cumin, 2 clove garlic and 1-inch ginger.
now add 3 tbsp mint / pudina, 2 tbsp coriander and saute for a minute or till it shrinks slightly.
cool the mixture completely, and transfer to a blender.
add 1 cup coconut, 2 tbsp putani, small piece tamarind, 3 green chilli and ½ tsp salt.
also, add ½ cup water and blend to smooth paste. add more water if required adjusting consistency.
transfer the coriander mint chutney to a bowl. keep aside.
now to prepare tempering, heat 2 tsp oil and splutter 1 tsp mustard seeds and few curry leaves.
allow the tempering to splutter and pour over chutney.
finally, serve coriander mint chutney with idli or dosa.