First of all take gram flour and rice flour in a bowl then add in rock salt, garam masala, salt, red chilli powder, pepper powder, clove powder, chaat masala, soda and water as per required.
Now mix all the ingredients well and make nice batter from it, consistency of batter should be sticky so that it can stick nicely on black grams.
Now heat oil in a pan, when oil gets heated lower the heat, while frying the heat should medium, now put the black grams in batter and dip nicely then put them in oil for frying one by one.
Make sure that layer of batter on black grams should be thin so they will be crispy otherwise they become soft and taste not good, cook them till become golden brown then take out in a bowl and let them cool.
Now take another bowl and put chaat masala, rock salt, garam masala, red chilli powder and mix all the spices well, sprinkling masala is ready.
When namkeen chana bhujia become cool sprinkle the masala on it and mix well and serve.