Mix idli batter and water well.

Heat a cast iron tava. Once the tava is medium hot sprinkle some oil and spread with a cotton cloth or cut onion or potato.

Take a ladle full of batter and spread into a very thin dosa.

Spread some ghee over the edges. Also drizzle some ghee all over the dosa.

let the dosa cook well and edges crisp up

Now using the handle of the spatula make a perpendicular cut from the center of the dosa.

Using the spatula roll the dosa into a cone. Serve ghee roast dosa hot with chutney and sambar