Take oil in a kadhai and heat it for deep frying.
When the oil is medium hot. add a small amount of batter to the oil. It should come slowly to the surface. It means the oil is hot at the right temperature for frying or not.
Take the batter with a spoon and add it to the kadhai. Or, you can put the batter in the oil from your hands.
Fry the vada well from both sides and fry it in medium flame so that it is cooked from the inside too.
Now, once it is cooked from both sides it means it is cooked from the inside. Remove it in a tissue paper
Take a big bowl of water and heat it
Add ½ tsp salt, ½ tsp sugar (optional), hing (optional)
Allow it to dissolve in water
The temp of the water should not be too high, (Check water temp by taking it in hand)
Now, add vada into the water and soak it for 10-15 minutes.
Then, take vada and squeeze it with light hands. Do not press tightly, otherwise, they can break.
This process makes the vada light and also removes the oil from it.