To begin, soak the chana dal for 3-4 hours. Drain out the water and let it stand for at least half an hour.
Grind the dal coarsely without adding any water. If you are using a mixer grinder, give it 4-5 pulses.
Transfer the mixture into a bowl. Add in the onions, ginger, green chillies, curry leaves, salt to taste, black pepper, and hing. Mix well.
Heat oil for deep frying.
To make the vada, shape the mixture into a lemon size ball and press it down between your palms. It should be thick in the middle and thinner on the edges. Prepare the other vadas similarly.
Deep fry the vadas on medium heat until golden brown and crisp.
The Parippu Vadas are ready to serve. Serve them hot with your favorite chutneys.