Cut the edges out of the bread.
Combine all ingredients under "for chutney" in a grinder and grind into a smooth mixture.
Spread the chutney on top of a bread and close with another bread to make a sandwich. Keep in your bowl. Repeat with the other slices of bread till done.
Spray some salted water on the bread sandwich just to make it wet, do not put too much.
Whip the yogurt, sugar and salt together and spread a layer on top of the bread.
Rest in the fridge covered with cling film, for an hour.
At the time of serving, heat oil. Splutter the mustard and cumin seeds. Fry the curry leaves and red chillies briefly. Pour over the set bread dahi vada.
Serve immediately.