Put the chickpea flour into a large mixing bowl. Slowly add 250ml/9fl oz water, mixing with a wooden spoon to make a smooth batter. Add the salt, cayenne pepper, ajwain seeds, onion, ginger, chillies, garlic and coriander. Stir and set aside for 15 minutes.
Smear a large, wide, non-stick frying-pan with 1 tsp of the oil and set over a lowish heat. When very hot, stir the batter and pour about 55ml/2fl oz on to the centre of the pan. Quickly tilt the pan in all directions as you would for a crêpe, spreading the batter to make an 18-19cm/7-7½in pancake.
Cover and cook for 3 minutes or until the pancake is reddish-brown at the bottom. Dribble another tsp of oil around the edges of the pancake. Turn the pancake over and cook, uncovered, for a further minute or until golden. Remove from the heat and keep covered between 2 plates. Repeat with the remaining batter. Always remember to stir the batter before you use it. (leftover batter may be covered, refrigerated and re-used).