Using a saucepan, lightly roast all three flours just until they are warm to the touch and become fragrant.
Chop the onions finely.
Combine all the ingredients except the oil and mix well. Do not add any water to the mixture.
Set aside for 30 minutes and let the onions release their juice.
Lightly mix the dough with your fingers and form balls that are the size of a small lime.
Heat the vegetable oil in a heavy-bottomed pan until it starts to ripple slightly.
While the oil is heating, shape each ball of dough in your palm into a flat disc. The discs should be about quarter inch thick. Thinner discs will be crisper, but make sure they don't lose the slight flakiness in the middle. I usually fry a test batch and then adjust the thickness of the discs.
Fry the vades in batches on medium-low fire until they are golden brown. Drain on paper towels.