Sift the refined flour, semolina, salt, and baking powder together. Add hot oil and mix Well. Knead with enough water to make a smooth dough. Divide the dough equally into tiny balls. Roll each out into a very thin disc, 1½ "in diameter. Perforate each with a fork so that it doesn't puff out while frying. Keep aside for 30 minutes, uncovered.
Heat the oil in a wok (kadhai); deep-fry the discs on a medium flame till crisp and golden. Remove with a slotted spoon and drain the excess oil on absorbent kitchen paper towels. To serve, arrange the fried discs (papri) on a plate; spread the potatoes, chickpeas, tamarind and mint chutneys, yoghurt and chaat masala to taste.