Mix chickpea flour, buttermilk, salt, turmeric powder, ginger and green chili paste and lemon juice in a bowl.
Take care not to form any lumps.
If a few lumps are there, just strain the mixture through a sieve.
Grease a smooth work surface very lightly. (I used my kitchen counter. You can also grease the back side of steel plates or a baking tray. )
Heat the mixture on medium heat till it thickens to the right consistency. ( It will take approx 30-35 minutes. To test if the mixture is done, pour a drop of it on a plate and spread it a little bit and let it cool. Now try to roll it. If it rolls, the mixture has reached the right consistency. Otherwise keep cooking it a little more. )
Keep mixing continuously otherwise the mixture will burn from the bottom.
Pour the mixture on the greased platform.
Quickly spread the mixture in a thin layer using a spatula or spoon.
Let it cool for a few minutes.
Cut into thin stripes. ( If you have OCD like me, use a ruler to get equal size stripes :) )
Roll the stripes.
For tadka, heat oil in a pan.
When the oil is hot, add mustard seeds.
When the seeds starts crackling, add sesame seeds, heeng, curry leaves and green chili.
Pour the tadka over the khandvis.
Garnish with fresh coriander and grated coconut.
Making Khandvi is a tedious process but the result is worth the effort. Don't give up on mixing the mixture while making it.You can easily double or triple the recipe.The mixture sets very quickly while spreading. Be quick to spread it thinly.