Channa dhal - 1 cup (soak for an hour and drain completely)
Jeera - 1 tsp
Ginger - half to 1 inch piece, chopped
Coriander leaves - 2 tbsp, chopped
Curry leaves - few, chopped
Onion - half medium, chopped
Oil - about 1 cup for deep frying
Note: I measured the oil before and after frying the vadas and calculated that I used about 5 tbsp of oil to fry this quantity. So even though these are deep fried, they are not all that bad (works out to 3/4 tsp of oil per vadai) . Keep in mind though that if the batter is too watery and the temperature of the oil is not right, then it will absorb more oil.