In a wok add the oil and let it heat on medium.
In the meantime, make round balls of the potato mixture.
Take a lemon size potato mixture in your hand and press it with your hand as if making ladoos or truffles.
Keep them aside.
Check if the oil mix is ready. Drop a tiny ball of the gram flour batter in the oil. If it comes up instantly the oil is ready.
Slowly drop the potato balls in the besan/gram flour batter and evenly coat it.
Drop this in the hot oil. Be careful not to put your hand in or not dropping it from a height.
Let this cook on medium for 2-3 minutes, until you see the bottom getting a bit cooked.
Using a serrated spoon, gently put some oil on the top.
I do this step so that when you turn the batter does not stick down.
Flip and cook on the other side.
Fry this for 7-8 minutes on medium heat turning in between until golden brown from all the sides.
Remove it on an absorbent paper.
Repeat the process for the remaining vada's.
If you are frying green chilies, do this in the last as the oil gets the spicy chilly taste.
First, slit the chilly in between and then fry for 3-4 minutes turning in between.