This dish is good served with rice and vegetable curries. Panch phoran can be made from my recipe #482606. You can find all of these ingredients in an Indian spice shop or deli. If you double the recipe, cook time will need to be doubled also.
In a bowl, rinse the lentils and mung beans well and pick out discolored beans. Drain in a sieve and put into a heavy pot with the salt and cold water. Stir and bring to a boil. Reduce heat to low and simmer for 25 minutes, stirring occasionally, to prevent sticking. When lentils are tender, remove from heat.
Heat oil in a small skillet over medium-high heat. Add asafetida and panch phoran, stir and allow spices to sizzle, about 30 seconds.
Add tomato and turmeric. Work mixture with wooden spoon into a puree. Cook about 3 minutes.
Add tomato mixture to the cooked lentil mixture and simmer about 5 minutes.