Wash and soak the moong dal for at least 4 to 5 hours.
Drain over a colander and grind to a smooth paste along with green chillies and ginger.
Add salt and adjust spice if required.
When the cooking oil is hot, take small portion of batter, maybe around 2 tsp, flatten it and gently slide it into hot oil.
If you are not used to making vadas, this step is quite tricky, so you can use either use your palm or a flat steel bowl inverted.
Wet the surface, pat down the ball and quickly transfer to the oil.
Cook on medium flame to ensure the vada is cooked on both sides.
Drain and soak in water to remove excess water. Let it stand for a while, then squeeze to remove excess water and soak in the Kanji.
Let this ferment at room temperature overnight and then store it in the fridge.
This stays good in the fridge for 2 to 3 days.