Coarsely crush coriander, cumin and carom seeds by hand in pestle and mortar.
Sift the gram flour and add all the spices in it and mix it into a batter with approx1/3-3/4 cup of water, it should be neither too thick nor too thin.
Slit open the green chilies length wise from one side. don't cut them through and through just make a slit and open them.
Fill them with chat masala and close the slit. some people remove the seeds of chilies before filling chat masala.. Bajia did not remove the seeds.
Put the oil in frying pan to get hot and meanwhile peel the potatoes.
Slice potatoes in neither very thick nor very thin slices.
When oil is hot, dip the chilies and potato slices in batter one by one and immediately put them in oil for frying, don't hold them for long otherwise the batter will start dripping.
Fry them until they are golden in color.
Put these on absorbent paper to absorb excess oil and then serve.
IMPORTANT TIPS BY BAJIA:
It is necessary to siftgram flour otherwise there will be lumps in the final batter.
Don't grind the coriander,cumin and carom seeds in grinder it will change the taste, grind them coarsely in pestle and mortar.
Don't overfill the green chilies with chat masala otherwise they will not close and the chat masala will come out in oil.
If the batter will be too thick it will not stick to the vegetables and if too thin and runny it will fall off. so keep it at proper consistency.
Always fry them in increments on medium to low constant heat for better results.
These taste good with roti, as in olden days people used to eat them with roti/chapati.