To make the Kumaoni Bada, rinse and soak dal overnight in enough water or for at-leat 6 hours.
Next morning you will notice the the black peel of the dal start leaving the white skin underneath.
Rub the dal in small batches in between your palms to remove the black peel. Each time drain the black peel.
After 2 - 3 times you will end up with majorly white skinned dal with few black peel here and there.
Let the dal sit in colander for 10 - 15 minutes for excess water to drain off.
Now grind the dal in small batches in the mixer. Make sure not to use any water while grinding the dal.
To get the smooth paste you need to stir the dal few times while grinding. Grind, turn off the mixer, stir and then grind. Repeat the process till you get thick, smooth dal paste.
Transfer to a clean, large bowl.
The trick to make crisp, fluffy vada is to whisk the dal till it is light and airy.
You can whisk the dal using electric hand blender or manually. The traditional way it is done manually. A continuous whisking of 10 - 15 is good enough to incorporate air in the dal.
Add hing, chopped coriander, green chili, spices and salt in the dal paste. Stir to combine.
Heat mustard oil in a wide deep frying pan over medium heat.
To shape the vadas, keep water in a small bowl next to dal paste.
Soak your fingers of both the hands in water and pinch a lemon size portion of dal paste. Hold it over your one hand fingers and flatten it using the other hand wet fingers.
Make a hole in the centre of the flattened vada.
Gently slip it on to the pan of hot oil to deep fry. For safety reasons, it is best to slide the shaped vada from the sides of the pan.
Deep fry the vada over medium high heat till deep golden, crisp from both the sides.
Transfer to a plate lined with kitchen towel. Serve Kumaoni Bada warm.