In a large bowl, add 1 cup of chana. Add water and rinse it few times.
Drain the water. Add some more water and keep the chanas soaked overnight or for 5 to 6 hours.
After 6 hours, drain the water and transfer the soaked chanas to a pressure cooker.
Add 2 cups of water. Add salt and pressure cook for 4 to 5 whistles.
In the meantime, blend ginger, garlic & green chillies to a fine paste. Keep this aside.
Open the pressure cooker once the steam has escaped completely.
Strain the chanas and keep aside. Reserve the water in which chanas were cooked.
Heat 2 tbsp oil in a pan. Add mustard seeds, cumin seeds and asafoetida.
Add chopped onions and saute.
Add a pinch off salt to the onions. Adding salt helps the onions to cook faster as they absorb moisture from the onions.
Once the onions have turned golden brown in colour, add ginger garlic and green chilly paste.
Saute for few seconds.
Add chopped tomatoes. Cook till the tomatoes are soft and mushy.
Add turmeric powder, red chilli powder, cumin-coriander powder and garam masala.
Add boiled chanas. Add the reserved water gradually, little at a time as per the desired consistency of the gravy.
Mix well. Add salt if required. Mash a few chanas using a masher to thicken the gravy.
Cover and cook on low heat for 2 to 3 minutes allowing the flavours to infuse.
Garnish with chopped coriander
Chana Masala is ready to be served.