Grease a flat plate and keep it ready before proceeding to cook Khandvi.Beat curd and keep aside.
In a bowl, add gram flour, salt, ginger-chilli paste, beaten curd, turmeric powder, asafoetisa and water and mix well to form a smooth batter (Ensure that the batter is thin and free of lumps).
Heat oil in a thick bottomed kadhai and add batter. Stir the batter continuously till well cooked.
(You will know that the batter is ready, when the batter take a light brown tinge & glaze from the oil and do not stick to the walls of the kadhai).
The batter should still be in a semi liquid state, tipping more towards solid state (Over cooking will result in a solidified mass which will not spread evenly).
Transfer the cooked batter onto the greased plate and spread uniformly into a thin sheet over the flat surface with a ladle.
(Do this quickly or else the batter will thicken as it cools and become difficult to spread.) Using a knife, make strip marks on the sheet.
Carefully roll each strip into spirals and place the khandvi rolls on a serving platter.
Heat the rest of the oil in another kadhai, add mustard seeds and let them splutter. Pour the tempering over the rolled khandvis.
Garnish the Khandvis with grated coconut and chopped coriander leaves and serve.