In a mixing bowl, sieve the cornflour and gram flour together.
Add salt, red chilli powder, cumin powder and mix well.
Add water and make a thick batter that will cover the onion rings.
In a frying pan, heat oil sufficient for deep frying.
Once the oil is hot, check for the correct temperature by dropping a small drop of batter into the oil. If the droplet rises immediately, that means the oil is hot enough to start cooking. If the droplet rises immediately and starts turning brown immediately, then u have to reduce the flame and wait till the temperature of the oil is reduced.
Start dipping the rings of onions and lift so that the rings are covered with the batter. Drop these battered rings into the hot oil.
Fry till golden brown on a medium flame.
Transfer these old fashioned onion rings to a kitchen tissue so as to absorb extra oil.