Combine flour, salt, oil and water and knead semi soft dough. Cover with dump clothe and keep aside to rest for atleast 30 minutes.
Now combine mashed potatoes, chopped onion (green and white both), salt, pepper powder, green coriander and green chilies in separate bowl and mix well and keep aside.
Divide the dough and stuffing both into equal four portions. Take one portion and roll it as thin chapatti.
Place the one portion of stuffing in center and spread it in half. Fold the bottom half up over the top half and seal the edges.
Repeat the same with the remaining dough and stuffing.
Heat the tawa on medium flame, grease with little oil and shallow fry the bolani one by one from the both side till tol golden brown and cooked.