Soak the dried peas in water for 18 hours. Change the water every 7-8 hours.
Boil the potato and let it cool for 5-6 hours.
After the peas have been soaked, cook them with some salt and twice the quantity of water.
Chop the onions, tomato, potato finely, and julienne the ginger.
Once cooked, keep the peas on low flame and keep mashing the peas lightly, till you get a slight creaminess. Take it off the flame. Add all the ingredients. The tamarind, lime, salt, chilli and chaat masalas are all dependant on your own palate. You can make it as spicy or as mild as you like. Matar ki chaat is ready!