Heat up the oil in a karahi or wok to a medium heat.
Slice the onion lengthways very thinly and place in a bowl. Peel and grate (or very finely chop) the potatoes into the same bowl. You can also use aubergines and cauliflower - chop into very small pieces.
Sprinkle all the dry spices and freshly chopped coriander, chillies and ginger into the bowl and then sieve in the gram flour - mix together using your hand.
Add a small amount of water a little at a time to create a thick batter that coats all the vegetables. Squeeze the mixture through your fingers to ensure all the spices mix through. Do not leave the batter and vegetable mixture for too long before cooking.
Test your oil is hot enough by dropping a little batter into the oil. If it browns and rises immediately then it is ready. Very carefully drop in spoonfuls of the mixture into the oil and fry until golden brown.
Using a slotted spoon move the pakora around, be careful not to overcrowd the karahi. Once golden brown and crisp remove from the oil and set on some kitchen paper to drain. Transfer to a serving plate and enjoy warm or cold.