First peel off the raw banana skin, making sure there are no green patches left. Keep them immersed in water until ready to use. This will avoid the darkening due to oxidation.
Meanwhile heat oil for deep frying. Once the oil is hot, set it on medium flame. Slice the banana into thin chips.
Drop each banana slice into oil and fry for a minute on each side until they are crisp and golden.
Drain off the excess oil and remove them on to a kitchen tissue. Repeat this with rest of the bananas.
Add salt and red chilli powder along with asafoetida (if using), mix well so that the chips are coated well.
Once cooled down, store in an airtight container. Stays good for 3-5 days outside.