Wash the Rajma (red kidney beans) and soak in water for 8 to 9 hrs or overnight.
Drain the water in which rajma are soaked and transfer them in pressure cooker with water.
Add salt, ginger and garlic and put the lid of cooker on.
Put the pressure cooker on flame upto 16-18 whistles.
In the mean time, prepare the gravy for Rajma and for that heat mustard oil. Once oil smokes, switch off the flame and let oil cool down a bit.
In a separate small bowl add bay leaf, cumin seeds, cinnamon stick, mace, nutmeg powder, coriander powder, green cardamom, black cardamom, and cloves and put all of them together in oil. I generally mix up all masalas seperately and them add them together in oil. This way spices get equal time to cook and also initially added spices don't expose to burning.
Let cumins splutter and then add onions and cook till they become brown in color.
Add red chilli powder, turmeric and mix.
Add grated tomatoes and salt. mix.
Cover the pan with a lid and let tomatoes cook for 10 to 12 minutes.
When oil is seen separated from tomatoes, its signal that tomatoes are properly cooked.
Transfer boiled rajma from pressure cooker to pan and mix.
Add tamarind pulp and mix well.
Let rajma simmer for about 10 minutes on low flame.
Smash few of the rajma beans against the wall of the pan with the help of ladle. Don't overdo, otherwise there will remain no piece of rajma left and everything will become a pulp.
Add garam masala and mix it well. Its ready now. Garnish with coriander and Roasted cumin seeds.