Wash and soak red rice and methi seeds for 7 hours.
Wash and soak udad dal for 7 hours.
Drain the water and grind udad dal to a smooth paste.
Transfer udad dal batter to a large vessel/bowl.
Next, drain the water from rice and transfer to a mixer jar. Add water as required and blend to a fine paste.
Add rice batter to udad dal batter. Add salt and mix well.
Cover the vessel/bowl and keep aside for 8 to 10 hours for fermentation.
After 10 hours,the batter would have fermented and doubled in quantity. Mix the batter gently.
Grease the idli plates with oil. Pour the idli batter into idli plates.
Arrange the idli plates in idli stand.
Place the idli stand in a steamer in which water is boiling.
Steam for 20 minutes. Serve red rice idlis with chutney and sambar.