Put the whisked yoghurt and flour in a bowl and mix together.
Then strain the mixture through a sieve (strainer) and set aside.
Put the onions, chillies, coriander, ginger, garam masala, fenugreek, turmeric and chilli powder in another bowl and season with salt.
Mix together and set aside.
Pour both mixtures into a large pan, stir, and lightly fry over medium heat ensuring that it does not stick to the base (bottom) of the pan for 5-10 minutes, or until thick.
Remove from the heat and allow to cool.
When the mixture is cool, divide into 16 equal portions.
With damp hands, roll into balls and flatten into patties.
Heat the oil for shallow-frying in a deep, heavy-based pan over medium-high heat.
Working in batches, shallow-fry the patties for about 3-4 minutes, or until they are golden brown and crispy.
Remove with a slotted spoon and set aside while you cook the remaining patties.