Mix the curds with 1 1/2 cups of water.
Combine the besan, curds-water mixture, lemon juice, ginger-green chilli paste, turmeric powder, asafoetida and salt in a deep non-stick pan and mix well to make smooth

Cook on a slow flame, while stirring continuously till it becomes thick
Grease a thali on the reverse side using oil and spread a batter on a greased thali and wait for a few seconds and try to roll

For the tempering, just before serving heat the remaining 3 tsp oil in a small non-stick pan and add the mustard seeds.

Pour tempting on khandvi and serve