Wash, rinse and drain urad dal. Soak it in water overnight for 4-5 hours.
1 Cup raw Urad Dal (Split Black Lentil)
Then drain all the water and transfer the urad dal to a mixer grinder. Also add jeera (cumin seeds) and salt.
1/2 Teaspoon Cumin Seeds (Jeera), 1/2 Teaspoon Salt
Add water in small increments and grind the mixture to make a batter of thick lumpy consistency. Beat this batter for at least 4-5 minutes to make light and fluffy vadas. Then let it sit for 10 minutes.
3/4 Cup Water
Pour spoonfuls of batter in the oil. You can also take small portions of the batter between your fingers and gently drop them in the oil.
Deep fry the dumplings in batches on medium heat till they are light golden brown.
Take them out when they are cooked on both sides. Let them cool down for a few minutes.
Transfer the vadas to slightly warm and mildly salted water. Let them soak in water for 15-20 minutes. Then gently press the vadas to squeeze out the water and transfer them to a plate.
Whisk 2-3 cups of chilled yoghurt with 1/2 cup of water till smooth and pour it over the vadas. If you want you can also add 1/2 teaspoon of sugar to the curd as well.
Top it with 2 teaspoons of tamarind chutney. You can also add some coriander chutney as well.
Sprinkle around roasted cumin powder, red chilli powder and salt, as per your taste. Serve the dahi vadas chilled.