Once the dal has been soaked for enough time, in a pressure cooker take rajma and urad dal, add 3 cups of water to it. Add salt and pressure cooker it for about 8-10 whistles on a high flame, till both the urad dal and rajma have cooked thoroughly and softened. The urad dal should melt in the mouth and should not give any bite when eaten. It is very important to cook dal perfectly.