Soak dal in enough water for 4-5 hours.
Grind it to smooth paste. Add chopped garlic, hing, salt and chopped curry leaves.
Whisk it really well. And let it rest for another 10 minutes.
In a bowl add curd with 4tbsp of water and whisk it well. Add black salt, sugar and red chilly powder and mix well.
Now make vada and deep fry. Add the vada into the water till it turns pale.
Squeeze out the water and dip in the curd.
Wait for another 10 minutes so that the vadas absorbs curd and it becomes soft and tasty.