Wash dal nicely 2-3 times in running water.
Soak dal in enough water for at least 3-4 hrs.
When ready to make drain water from lentils and grind to a fine paste.
Add and mix rice flour.
Beat the batter to 4-5 mins for aeration, till it is light and fluffy.
Keep it covered for 10-15 minutes.
To check whether the batter is ready to fry, drop a small ball of batter in water(in bowl) it should float. Else, beat it little more.
Crush peppercorns and add to batter.
Add chopped onions, curry leaves, green chillies and cumin seeds with salt. Mix everything well.
Heat oil in a heavy bottomed pan or kadhai. Drop very tiny ball of batter in oil, it should rise slowly.It is the right temperature to fry vadas.
Fry Vadas first on medium to low flame and then on high flame.
Fry till light brown. Once done take out from oil and drain on tissue paper or kitchen towel.
Serve hot with chutney or sambhar.