Heat the oil in a pan to fry the puris
Check if the oil is hot enough by putting a small piece of pellet in it. If not, heat more.
Put one pellet in the hot oil and wait for it to start coming up (puffing).
As soon as the puri starts coming up, put some hot oil on it so that it can puff up easily.
Fry the puris quickly in batches of 4-5, handling them carefully because their color changes fast.
If the temperature of the oil becomes too high, lower the flame for a while and let the temperature go down.