Soak urad dal in the icy cold water (to get more batter) for 1 hour.
Drain the water completely.
Add salt,few curry leaves, hing, and grind to a smooth paste.

Add chopped onion, cabbage,ginger,green chilli, and curry leaves. Mix well with fork and
Heat the oil for deep frying in a wok.
Take little bit of the batter to make it to a round shape and flatten it slightly. Make a hole in the middle of the flattened batter, with your finger. Deep fry them well. Do not burn them. Remove from the oil and drain the excess oil well from the vadais. Serve it hot with Mint chutney.