Soak the urad dal and rajma in separate bowls filled with cold water for 24 hours or overnight.
If using a pressure cooker, drain and place the soaked legumes in the pressure cooker with the water and salt. Set over high heat until three to four whistles emit from the cooker. Reduce to medium and cook for another 15–20 minutes. Let the pressure release naturally. The lentils and beans should be soft enough to mash while still holding their shape. If they aren’t, return to the pressure cooker for a little longer.
Alternatively, boil the legumes in a large saucepan or slow cooker for about 90 minutes until tender, then mash.
For the main cook, melt the butter and ghee in a heavy-based saucepan over medium heat. Add the onion and saute for 5–7 minutes until translucent. Stir in the garlic and ginger and cook for another 2–3 minutes. Add the tomato paste and cook for 2–3 minutes, then add the masala.
Add the mashed lentil and bean mixture. Reduce the heat and simmer, stirring in the water in three stages, allowing it to absorb between additions. Stir regularly to develop a rich, creamy texture.
To finish, stir in the final butter, cream and chilli (if using). Serve hot with basmati rice and a simple vegetable sabji.
