Wash and soak urad dal for 2 hours and grind urad dal little at a time in a grinder without adding any water. If required add one tablespoon water to make the grinder work. Grind to a thick smooth paste. Add salt and mix well.
Wet your palms with water, take a small amount and form a ball.
Place in the center of the palm. Flatten and make a hole in the center, like a doughnut Or just make round balls and fry as round vada's.Wet the palm when shaping each vada. Water will prevent the paste from sticking to the palm.
Heat a kadai or a wok with enough oil to deep fry on medium heat.
When the oil is hot, carefully slide the vada/bhalle into the oil and deep fry till crisp and golden brown in colour. Drain excess oil.
Soak the Vada's in a bowl of luke warm water for 5 minutes and gently press each vada between your palms, to drain off excess water. Set aside
Beat curds well with salt as required in a serving dish. Add the vadas/bhalle to the beaten yogurt.
Garnish - Sprinkle red chili powder, roasted jeera powder, chaat masala powder and coriander leaves over the vadas. Serve the vada in a serving dish with tamarind chutney(optional)
Tip: Vada can be made in advance and stored in refrigerator. When needed......soak them in lukewarm water and follow the above method after soaking in water.