Pressure cook the potatoes till they are tender. Mash it to a fine paste using potato masher or food processor.
In a wide vessel, take wheat flour, mix salt, chili powder and ghee. Then, add the potato paste to the flour and knead well. Slowly add the milk and knead to a soft dough. Add water if needed.
Let it rest for 10 mins.
Then, divide into equal balls and roll out into small rotis.
Heat a pan and cook the rolled out rotis over hot pan on both sides, sprinkling oil/ghee.
The cooked chapatis are very soft as the potatoes are blended into it.