Make dosas right before serving. Place all ingredients for dosa in a bowl and 1 ½ cup water to make a batter like a crepe batter.
Heat a non-stic or cast-iron griddle. When the griddle is very hot, put a little oil and spread it on the griddle. Take some of the batter and spread it in a spiral motion moving towards the outward part. Put some more oil on the edges of the dosa.
Flip the dosa when it turns golden. After 20 seconds of cooking, remove it from the griddle and serve hot with white chutney and sambhar.