Take the whole wheat flour in a bowl, add salt, milk, yogurt and sufficient water and knead into a soft dough. Cover with a damp cloth and set aside for fifteen minutes.
Divide the dough into eight portions. Add onion to the mashed potato along with salt, red chilli powder, green chillies, roasted anardana powder, chaat masala, coriander leaves and salt and mix well.
Divide into eight portions. Roll out each portion of the dough into a small puri, place one portion of potato stuffing in the center, gather in the edges and roll out into a ball. Further roll into a parantha. Similarly make the remaining paranthas.
Heat a tawa. Place a parantha on it and roast for half a minute. Flip and pat on some water on the upper side. Flip again and pat some water on the other side too. Continue to roast till both the sides are evenly lightly browned.