In a mixture jar, add semolina (sooji/rava). Grind it into fine powder.
Now add grinded powder into the mixing bowl. also, add curd and water gradually and make a thick batter.
Cover and rest the batter for 15 minutes.
Add 1-2 tablespoons of water and whisk the batter for 5 minutes till it becomes light and fluffy.
Then add salt, cumin seeds, green chilli paste and ginger paste. Mix well.
Now add baking soda and mix well with the batter. prepare a medium-thick batter.
Now with wet fingers or a spoon, drop a spoonful of batter into the hot oil.
keeping the flame on medium, stirring occasionally. fry until the vada turns golden brown and crisp.
drain off the vada with a wire rack to remove excess oil.
now in a large bowl take 5-6 cups of slightly hot water. add ½ tsp salt and ¼ tsp hing. mix well making sure it is well combined.
now drop the hot fried vada into the water and dip completely.
soak only for 10 minutes, so vada absorbs water and becomes juicy. Do not soak it for a longer time.
then squeeze off the water and transfer it to the plate.