Mix in semolina, curd, cumin, coriander, ginger, chillies, and salt to form a smooth paste. Let it stand for 10-15 minutes so that the semolina can soak up the liquids.
When ready to cook, add in two pinches of baking soda. Mix in well.
The consistency should be that of a soft kneaded dough (atta). Add in a bit of water if needed.
To make the vadas, wet the palm of your hand with water. Take a small ball of the mixture. Put it on the palm and shape it into a vada.
Fry them on medium heat until golden.
Serve hot with your favorite chutney.