Prepare idli dosa batter using Mixie or grinder. Keep it ready.
Wash carrot, beetroot and potato in running water well. Then peel the skin off from carrot, beetroot & potato with a peeler. Then chop them into equal size small cubes.
Steam the chopped vegetable cubes in a steamer for 15 minutes. I have used Philips avent combined steamer and blender for both steaming and blending.
Alternatively you can steam it with Idli steamer plate by adding a cup of water or pressure cook the vegetables together with a cup of water for 3 whistles. Once the vegetables are steamed, blend it to make a puree.
Now add the blended vegetables puree to the dosa batter along with cumin seeds. Mix well and keep aside.
Heat a dosa tawa. Once its hot, pour a laddle of batter to it. Keep the flame medium to low. Spread a liitle to form a small circle. Then sprinkle ghee over it. Then cook covered with a lid for 3 minutes