In a pressure cooker, add dal (lentils), tomato, green chilli, turmeric and salt with 2 1/2 cups water. Pressure cook till the dal can be easily mashed between two fingers.
This is completely optional, but if you'd like to smoke the dal, heat the pieces of coal over an open fire till they are red hot and add them to a small katori or heat proof bowl (steel works best). Pour ghee over it and place the bowl in the middle of the dal, making sure that it doesn't sink through. Cover and let the coal do it's magic for five minutes. After five minutes, remove the bowl and discard the coal.
In a small skillet or tadka pan, add ghee, garlic and red chillies. Let these heat up slowly so that the garlic imparts it's flavor. Once the ghee is hot, add cumin seeds. As soon as the cumin starts spluttering, add chili powder and switch off the flame. Pour this all over the dal and mix in chopped coriander.
Cover and let the dal sit for half an hour if you have the patience. Reheat and serve!