The night before: in a large bowl of water, soak the urad dal (make sure the dal is completely covered by water at least 3x over so it can expand).
Cook the dal: Drain the water from the bowl once the dal has expanded then place into a pot on the stove with 350ml of water and let cook for 30 minutes until the water has been adsorbed and the dal is mostly soft.
In the same pot, add to the dal the cooked kidney beans and mash the beans and dal with a potato masher until they make a soft paste and then simmer on low heat (adding water if needed) while you make the spice mixture.
Heat 2 tbsp of butter in a pan, once the butter starts to foam add the grated onion and cook for 5-7 minutes until the onion starts to break down.
Add the ginger and garlic, cook for just one minute then add the tomato puree and all the rest of the spices and mix to combine.
Add in to the dal-bean mixture to the pan and put heat to very low. Cook for 45 minutes, stirring every 5-10 minutes. Add more water if needed.
To finish, turn the heat off, add the cream and extra butter if desired, stir well. Adjust seasoning to taste and serve with naan, rice, or roti.
4 servings