Heat Oil on a medium high heat until the onions are sliced. Do not do it on a high heat at all. Otherwise they get burnt and the colour will be dark.
Slice the onions as thinly as possible. I have used a slicer for this. Fry them in hot oil on a medium high heat only keeping an eye on them all the while. Keep turning every now and then so that they are fried evenly.
As soon as you reach this point when they are almost done by 95% as seen in the pic below,switch off the heat. Keep turning them and immediately drain them on an absorbent paper and spread them. Using your hands, separate them all because some tends to stick. Let them cool down a bit so that they get crispy. This is all really for use now.
An excellent and important tip in this regard is that after they are done, spread them on a plate in order to separate all of them properly and then pop in the Freezer for about 5 minutes. Remove them and use as required. They will get super crispy.
These can be done in large quantities and stored in ziplock bags in the Freezer for almost an year. You will definitely save on a lot of time and efforts. And also remember not to throw away the Oil in which they are fried. It's very flavourful and hence can be used in Curries and Gravies.
