Wash the dal and soak in 3-4 cups of water for 4-5 hours.
Drain the water and add the dal in a blender along with ginger, green chilli and salt.
Blend the dal to make a thick paste. Just add 2-3 tsp of water while grinding the dal.
Use your hands and whisk the dal for 4-5 minutes until it is very light.
Cover the bowl and keep aside for 15 minutes.
Add the baking soda and whisk for another minute.
Take a bowl filled with water and drop small drop of batter in it.
If the batter immediately starts to float on top of the water, the batter is ready.
If not, then whisk it some more.
Heat oil for frying in a pan.
Wet your hands with water and take out small portion of the batter in your palms. Shape it into a flat round vada.
Drop the vada in hot oil. Simmer the heat to medium low and fry all the vadas until they are golden brown.
Drain on a plate.
For the soaking water
Mix all the ingredients in a bowl and keep aside.
Whisk the curd with sugar and salt and keep aside
Add the fried vada in soaking water and let them soak for 15 minutes.
Press the vada between your palm lightly and arrange them in the serving plate.
Top with whisked curd.
Top with coriander mint chutney and tamarind chutney.
Sprinkle dahi vada masala, red chilli powder, roasted cumin powder, salt and fresh coriander.
Chill for a few hours in refrigerator.
You can stuff the dahi vada with a mixture of cashew nuts, coconut, raisins and ginger. Just chop these ingredients and keep a little in the centre of the batter and cover it up with more batter.Do not add more water while grinding the dal. It will become difficult to shape it into vadas. Fry the vadas on medium low heat otherwise they will not cook in the centre.If you want to use the vadas later, just keep them in refrigerator for 2-3 days. Before using, dip them in soaking water for 20-25 minutes and then top with curd. To make soft dahi vada recipe with soft centre, the trick is to whip the lentil paste until it is very light and fluffy. After grinding the lentils to a fine paste in a grinder, whisk it using your hands for 2-3 minutes.Add a little baking soda while whisking it. Then take a bowl filled with water and drop a small ball of the batter in it. If the drop immediately starts to float on top, the batter is ready to fry.A pro tip to whisk your dahi vada batter is to use electric mixer to whisk the batter until it light and fluffy. It saves a lot of muscle work and the batter is soft as cloud. After experimenting this trick on my Indian style Coffee Recipe, I now use it for anything that needs a good whisking.Another tip to check if the Dahi Vada batter is whisked properly, you can turn the bowl in which your are whisking the batter upside down and the batter should not fall down. This is a little tricky because if the batter is not whisked well, it will fall down and you will have a lot to clean up :)While frying the dahi bada, fry them on medium heat and as soon as you drop them in oil, keep pouring oil over them using a ladle to seal the air inside.Double frying the vada also makes them crunchy from outside and soft from inside.Assemble the dahi vada 2-3 hours before serving. It allows the flavours to soak in the vadas. Just top with more chutney and spices at the time of serving and you are good to go.