Soak urad dal for 2 hours. Then keep it refrigerated for an hour. This helps in giving fluffy stiff batter while we grind in mixie.
Drain water and grind it with ginger, green chillies adding ice cold water little.
The batter will loosen when we add salt later, so add water very carefully and less. Batter should be smooth and thick.
Add coriander, curry leaves and salt and mix well. Keep refrigerated until use. Keeping refrigerated also keeps the batter stiff and thick helping to shape the vadai perfect.
Heat oil for deep frying.
Wet your hands and make shape of vada in your hands or in your convenient way of making vada shape and drop in oil carefully.
Fry 3-4 vadais at a time depending on your kadai and oil size.
Cook both sides in medium flame until golden.
Drain in paper towels.
Soak vadai in hot water. Make sure water is just hot, not boiling water.
Adding hot vadai in hot boiling water makes it loose it shape and not looks good. It may become too soft. So drain and cool the vadais, then add in hot water.
Let it soak for atleast 15 mins.
Meanwhile prepare curd – beat curd and milk with salt until smooth.
Temper with the items given under ‘to temper’ table and mix.
Drain water from the soaked vadai and slightly squeeze without changing the shape.
Place it in a serving tray.
Pour the curd mixture on top of it and let it get soaked.