Preparation / Directions:
Melt the butter in a large saucepan over a moderate heat. Add the mustard seeds and cover the pan. When you can hear the seeds popping, add the onion, garlic, and ginger root. Cook, uncovered, until they are soft and the garlic is brown, about 7 - 8 minutes.
Stir in the turmeric and green chiles and cook for 1 - 2 minutes until the chiles soften a little.
Add the lentils and cook for 2 minutes, stirring frequently, until the lentils begin to turn translucent.
Add the water, coconut milk, and salt. Stir well. Bring to a boil, then reduce the heat, and simmer for 40 minutes, or until the desired consistency is reached. You may like it more liquid than I do, in which case 40 minutes will be about right, but cook it longer if you prefer a thicker consistency. (However, if you intend to reheat the dal later rather then eat it straightaway, cook for only 30 minutes to allow for reheating time.)
Serve immediately while piping hot.