Add water to the Besan.
Besan has a tendency to be very clumpy, so you should add just a few tablespoons at a time to keep the batter smooth.
Add the Chilli powder, cumin powder, garlic, ginger, salt and chopped coriander and stir the batter.
The potatoes should be sliced very thinly.
No thicker than 1/4 of an inch.
At this point test one slice of potato in the batter.
There should just be a thin coat of batter.
Heat the oil in a pan.
Use a larger frying pan so that you have more surface area.
The oil doesn't need to be too deep since the potato slices are very thin.
Dip the potato slices in the batter and fry them till they are golden brown.
Remove them from the oil with a slotted spoon and set them on a paper towel for a minute to soak up the excess oil.