Heat a pan and dry roast the mung dal till it's light golden on a low medium flame. Let the roasted dal cool for 5 minutes. Take care not to burn it.
Wash the moong dal 2-3 times with water.
Add the roasted dal in a pressure cooker along with 1 and 1/2 cup water, a pinch of salt and turmeric powder.
Cover the lid of the pressure cooker with the whistle and let it cook on a medium-high heat. After 2 whistles blow, turn off the gas and let it cool for 15 minutes.
Heat a pan and add 2 tsp of oil or ghee
When the oil is hot, add asafoetida, cumin seeds, dry red chillies, cinnamon stick, bay leaf, cloves and cardamon pods. Saute for 2-3 minutes on a low flame till you feel the aroma of the spices.
Add the grated ginger and green chili, saute for 2 minutes till the raw smell of the ginger goes away.
Add the boiled dal, then add water as required for the gravy consistency.
Bring the lentil soup to a gentle boil on a low medium flame. Now add the roasted cumin powder and salt if needed. Lower the flame and let the dal simmer for 2-3 minutes.
Add sugar just before taking the lentil soup off the heat. (This step is optional.)
Garnish the dal with chopped coconut . Serve it hot along with rice or roti (chappati).