Soak dal separately for whole night. Next day grind it just like dosa batter.

For tadka : Heat oil in a tadka pan. Fry mustard seeds, kadi parts, whole red chilli and hing. Let it crackle for few seconds. Then pour in a dosa batter. Mix it well. Heat non-stick pan pour spoonful batter. Spread it evenly and make a round in shape. Cook for 1 minutes in a slow flame.

Then add idly powder and Desi ghee. If you add ghee the idly powder will stick to dosa. When you will eat it will be crispy. Once it is done. Fold the Rosa and transfer to a serving plate.