First cut the bread into small pieces, then put into a mixer jar and blend it smoothly.
Next add curd, water and 3 tsp of besan again and blend it well.
Now make a smooth batter and put this batter into a bowl. Add green chilli, ginger paste and mix it well.
Then take a pan, put this batter into the pan and cook on a high flame. Stir it continuously.
When it becomes thick in texture, lower the flame and cook it for 5 mins.
Check by spreading some batter on a thali, if it easily rolls out, then turn off the stove.
Now take 3-4 thalis, grease them with oil then spread 1 spoonful of the khandvi mixture on the thali. Keep them aside to cool.
Make two parts of the mixture, now add red colour on the khandvi mixture and mix it neatly. Also take another thali and spread it all over. Keep it aside to cool.
Now take the remaining portion of the khandvi mixture, add green colour and mix it properly then spread it on a thali. Now make the rolls out of the spread.
For the tadka, heat some oil in a pan, add in mustard, cumin seeds, hing, sesame, curry leaves and green chilli finely chopped (optional). Pour this over the khandvi and serve.