Wash Red Cholam, idli rice, urad dal, and javvarisi thoroughly. Soak each ingredient separately until softened.
Grind the soaked urad dal in a wet grinder by adding water gradually until it becomes light, fluffy, and smooth. Transfer it to a large bowl.
Grind the soaked javvarisi first, then add the soaked Red Cholam and continue grinding until smooth.
Add the soaked idli rice and continue grinding until the batter reaches a smooth, pourable consistency. Mix the Batter
Combine both batters and mix thoroughly using your clean hand until well incorporated.
Cover the batter and allow it to ferment overnight or until it becomes light and airy.
Mix the fermented batter gently, pour it into greased idli moulds, and steam until the idlis are soft and cooked through.
Stir the batter gently, spread it on a hot tawa, drizzle a little oil, and cook until golden and crispy.
