Wash urad dal 3-4 times and soak for 4-5 hours.
In a bowl, add fresh plain yogurt, salt, and sugar. Whisk to a smooth and creamy consistency and set aside.
After 5 hours of soaking urad dal, drain excess water and transfer it to a blender jar with cumin seeds, salt, hing, green chilli, sliced ginger, and water. Blend to a smooth and thick consistency batter.
Transfer the batter to a bowl, whisk or beat it for 2 minutes (use hand or spoon) to aerate the batter and get fluffy and light batter.
Heat a pan or kadai with oil for deep frying. When oil is medium hot, wet your palm(or use a spoon) and scoop a small portion of batter and place in hot oil.
Stir and evenly fry the vadas until they turn golden brown and crisp.
Place the vadas on a paper towel using the strainer to remove excess oil.
In a bowl of water, place the fried vadas and soak them for 20-25 minutes. Vadas will absorb water and change color.
Gently press each vada between your palm to remove excess water and place them on a serving plate.
Pour a generous amount of whisked yogurt on each vada and rest them for 15-20 minutes.
Top with the green chutney, sweet chutney, cumin powder, red chilli powder, chaat masala, and chopped coriander leaves.
Serve immediately or refrigerate for 2 hours.
Enjoy soft and delicious dahi vada!