Measure all the ingredients and add them to a bowl.
Wash them for a couple of times under running tap water, until the water is clear.
Now add enough water required for soaking. Let the millets and lentils soak for atleast 3-4 hours.
After 3-4 hours, drain all the water, give it a quick rinse and transfer it to a mixer grinder jar for grinding.
Grind it into a smooth paste (add water while grinding), mix the batter with your hand for a couple of minutes. It aids in fermentation.
Cover and keep the batter aside in a warm place for 8-10 hours (depending on weather) for fermentation.
After the batter has fermented, add salt, mix lightly and make dosas.
If you plan to stock and use this later, refrigerate the batter immediately after salt is added.
For making dosas - Heat a flat dosa tawa or griddle, add few drops of oil and season the pan well using a kitchen towel, potato piece or onion piece.
Once the pan is hot, pour a ladle of the batter and spread it clockwise until its thin and uniformly spread.
Pour oil on all sides, let it cook on medium heat until the sides are crispy.
Flip the dosas, add some oil and allow it to cook. Dosas should be served piping hot with an accompaniment of your choice.