Drain the soaked Rajma and pressure cook it with 3 cups water, salt, and whole spices like Bay leaf, Cinnamon, Cloves, and Black Cardamom.
After the 1st whistle, reduce the heat to low and cook for 20 minutes on low heat.
In a pan or Kadai, heat oil or ghee and drop in the cumin seeds. When the cumin seeds crackle, add the finely chopped onions and saute until golden brown.
When onions brown, add in the ginger-garlic paste and fry till the raw smell vanishes.
Next, add in the dry spices - red chilli powder, coriander powder, and turmeric powder. Fry this for a minute adding a splash of water to avoid burning.
Then add the tomato puree and salt and continue to saute till oil oozes out from the sides.
When the onion tomato masala becomes one mass, add in the boiled Rajma/Kidney Beans along with the stock. At this stage, you could adjust the gravy as required by adding warm water. Mix well and bring this to a boil.
Now reduce the heat and cover the vessel and cook for at least 10 minutes on medium to low heat or until the curry thickens.
Finally add garam masala powder, Kasuri Methi, and butter. Also, garnish the Rajma Curry with coriander leaves and then switch off the flame.