Wash the yellow moong dal very well and soak in enough water for about one hour.
After soaking for about one hour, discard the water used for soaking the dal and rinse the dal again lightly in fresh water.
Grind the moong dal in a food processor or blender along with enough water, salt, green chilies, cumin seeds and ginger until the ingredients are well blended until smooth.
Transfer the batter to a bowl or container and keep it closed for another 30 minutes for best results.
After 30 minutes of resting time, the batter is ready to be used, just stir once again and you can start making dosas.
To make dosa, heat a non stick pan or iron pan and grease with oil or ghee.
When the pan is hot enough, add one ladle of batter and spread it thinly across the pan by moving the ladle in circles through the batter, just like you do for regular dosa.
Add one teaspoon of oil or ghee evenly, wait for the dosa to get cooked on the bottom side which will take around 1 to 2 minutes of time. Keep the heat at medium and adjust as needed.
Once the first side is cooked, gently flip the dosa using a good spatula, starting by separating from the sides first.
Cook the other side of the dosa too, which will take about a minute or so.
Transfer the cooked dosa from the pan to the serving plate. Serve hot with any sides like coconut chutney, sambar or any chutney of your choice. Similarly make other dosas too and serve all dosas hot, as dosa tastes the best when served hot. Save any remaining batter for later use, if saving for next day, you can store the batter in refrigerator.