Wash and soak urad dal overnight.
Place the urad dal in a sieve to drain all the water
Add it to a mixer grinder, add a tablespoon of water at a time (I used between 4-6 tablespoon water), and grind it to a smooth paste. You may need a little less or a little more water, but try to use as little water as possible. This entire process can take up to 6-8 minutes. It's important to keep mixing it with a spatula and grinding.
Mix salt and hing in the ground urad dal and set it aside for ten minutes. The hing acts as baking soda and helps make the batter lighter.
Place the oil in a kadhai for heating while you whisk the batter
Use a hand whisk to whisk the ground urad dal until it's light and fluffy - approximately 5 minutes. You’ll feel the batter becoming airy and fluffier and also getting lighter in colour from a yellow to pale white.
Once the batter is whisked, mix in rice flour, jeers, crushed peppercorns and coriander. Add another teaspoon of water if required. Whisk again for a minute or two
To make vadas, dip both your hands in water. Take a lime-sized amount of batter in your dominant hand (in my case, my right hand) and place it on the palm of the subservient hand (in my case, my left hand). Using the fingers of the dominant hand, form it into a circle and then make a hole in the centre. Dip the dominant hand in the water again, and place the formed vada on the fingertips of the dominant hand.
Gently drop the vada in hot oil by turning the hand over the kadhai (close to the oil so the vada doesn't splash into it) and moving the fingers slightly so the vada slides into the oil.
You should see it start to puff up slightly. Cook it on a medium flame for 2-3 minutes till golden brown on both sides.
Repeat till all the vadas are fried. Serve hot with piping hot sambar and chutney.