Soak whole black urad, chana dal and rajma overnight in 3-4 cups of water.
Cook the soaked dal and rajma in the same water with salt, red chili powder and half the chopped ginger till dal and rajma are cooked and soft.

Peel and chop the onion, ginger and garlic finely. Also chop the tomatoes.
Heat oil and butter in a thick-bottomed pan. Add cumin seeds, when it crackles add chopped onions and fry till golden brown.
Add chopped ginger, garlic and chopped tomatoes. Sauté till tomatoes are well mashed and fat starts to leave the masala.

Add boiled dal and rajma to this.Crush(mash) the dals with the back of the ladle while stirring continuously, this gives that creamy texture to the dal.
Add some water if required and simmer on very low heat for fifteen minutes.