Khandvi is made with a mixture of gram flour and buttermilk. In india what we call buttermilk is a thin solution of yogurt and water. Cooking this smooth batter of the gram flour and buttermilk batter is one tricky part. What we look for in a khandvi are thin layers and this is achived by getting the right consistency thickens, then spreading the khandvi mixture becomes difficult and what you get are thick layers. Another import point is that you have to be quick in spreading the cooked khandvi batter. Khandvi is a gluten free healthy snack if you do not add asafoetida powder or use wheat free asafoetida. The recipe can also be veganized using vegan yogurt. To get the sourness just add a bit of lemon juice in the batter.