Measure and add the raw rice, black urad dal, pepper and cumin seeds into a bowl.
Wash them couple of times under running water. Drain and then soak them with 2 cups of water for atleast 3 hours.
Drain all the soaked water, add the ingredients to a mixer grinder jar and grind them coarsely (use some water to grind)
Once ground, add sliced coconut pieces, hing, salt to taste and curry leaves.
Mix well and adjust the batter consistency if its too thick by adding some water.
Once the batter is ready, heat a pan, season it with some oil once its hot and then pour a ladle of batter.
Spread it carefully, make a small hole in the centre and pour some oil in the centre and on the sides.
Let the adai cook (it will crisp up on the sides), turn them over and then cook further for a couple of minutes.
Serve it hot with vellam (jaggery) and butter.