Soak dried peas in three cups of water for about six hours. Drain and boil in three to four cups of water with turmeric powder, asafoetida and salt till soft. Mash the peas slightly.
Add a little water if too thick and simmer for ten minutes. Keep the ragda hot. Add cornflour, green chillies and salt to potatoes and mix well. Divide into eight equal portions and shape into balls. Flatten slightly.
Heat a little oil in a frying pan and fry pattice gently on both sides on medium heat till evenly browned. Keep warm. To serve, place two pattice on a plate and pour ragda on them.
Drizzle green chutney and sweet date and tamarind chutney, sprinkle onions, chaat masala and coriander leaves. Similarly make other servings. Serve immediately.