For the Chickpeas:
1 cup chickpeas
1 bay leaf
1 inch piece of cinnamon stick
1 whole cardamom
2 cups of water
2 cups of buttermilk
1 tsp turmeric
salt as per taste
2 tsps curry leaves
2 - 3 tablespoons of finely chopped fresh coriander (optional)
Wash the chickpeas, soak them overnight in enough water. Drain and rinse. Place the soaked chickpeas with water to cover them in a pressure cooker. Pressure cook along with bay leaf, cinnamon stick and cardamom. After one whistle, reduce the heat to low and cook for roughly 15-20 mins when you think they would be tender.
Remove the cinnamon stick, cardamom pod and bay leaf and set the chickpeas aside along with the water.
In a medium bowl, mix the gram flour, water, buttermilk, turmeric, salt and keep it aside when mixed well.
In a large pot, heat oil, add mustard seeds and curry leaves. Add chopped onion, and add the tomato when onions are done. Cook for a bit, then add the coriander powder and garam masala. When the masalas are cooked, add the buttermilk mixture and bring to a boil on moderate heat, stirring constantly. Add the cooked chickpeas along with the water,bring to a boil, and simmer for a couple of mins. Remove from heat. Add coriander and serve hot.