For the dough:
In a bowl put the flour, salt and oil
start adding the water a little at a time and start kneading the dough.
Make into a semi soft dough adding water as necessary until the desired texture
Divide the dough into 10 balls
For the filling:
Mix together the onion, salt, curry leaf, pepper and green chilies, add in the mashed potato and drained tuna. Mix thoroughly.
To prepare the roshi
Take a piece of the prepared dough and make a dent.
Stuff with about a tablespoon of the filling and close it to make a round ball
Dust the ball with flour and roll out into a flat bread, use additional flour as necessary
Heat a pan and put in the roshi adding a touch of oil to each side of the roshi.
Cook until lightly browned.