Black dahl

Steps

1. Put the dal into a large bowl, cover with water and whisk for 10 seconds. Let the dal settle then pour out the water.
2. Repeat until the water is clear. Tip the dal into a saucepan and add four litres of cold water. Bring to a boil and cook steadily for two hours.
3. Skim off any impurities that rise to the surface, and add more boiling water as required to keep the grains well covered. Turn off the heat and set aside for 15 minutes.
4. In a bowl mix the garlic and ginger, tomato puree, salt, chilli powder and garam masala into a paste.
5. Pour off the dal cooking water then add boiled water to cover the dal by 3cm. Bring to a boil over medium heat. Add the paste and butter. Cook for 30 minutes, stirring regularly.
6. Lower the heat and simmer for an hour, stirring regularly, add boiling water if the liquid level gets to near the level of the grains.
7. Add the cream and cook for a further 15 minutes.