Boil potatoes. Peel and grate. Put them in a bowl, add salt and mix. In another bowl, take boiled urad dal. Add coriander leaves, green chillies, black salt, asafoetida, ginger, half teaspoon chaat masala, half teaspoon red chilli powder and mix well.
Knead the grated potatoes. Apply oil in hand. Take a portion of mashed potatoes, make a dent in the center and put the dal stuffing. Cover and shape into a tikki. These tikkis should be thick and round.
Heat oil on a tawa, place the tikkis on it and shallow fry. When one side is golden, turn over and fry till the other side is also golden.
To serve, take a tikki on a plate. Open it in the center and put matara on it. Put some yogurt, sweet date and tamarind chutney, green chutney.
Sprinkle cumin powder, black salt, remaining chaat masala powder, remaining red chilli powder. Crush a few papdis and top up the chaat with it.