Ingredients:
Dosa flour - available in indian stores, ready to pour into the pan
Potatoes, green chilies, onions, coriander

Preparation:
Pour a teaspoon of oil onto a non-stick pan. As it heats up, add mustard seeds, and as it crackles, add in the onions and green chillies. Add chili powder, salt and turmeric. Mix and fry the mixture.
Add in the boiled potatoes into the mixture and fry. Constantly stir and mash in.
This is the Masala.

Pour the dosa batter into a dosa pan and using a cup spread the batter into a circle like a pancake or crepe. Add a few drops of oil. Once the bottom side is done, turn the dosa around. Turn it around one last time, add the masala and fold the dosa into a box.

Tip: To get the box, cut the dosa like a cross and fold over.