Wash and soak the lentils for at least 2 hours. Cook with turmeric powder, ground ginger, red chilli powder, 1 tsp ghee and salt till soft and mushy.
Heat ghee in a small pan and add mustard seeds and cumin seeds. As it beings to splutter, reduce heat and add sugar and asafoetida. Stir for 15 seconds and add to the mashed dal.
Place the dal on medium heat and add coconut, zest and juice of 1 lemon and season with salt if necessary. Bring to boil and then simmer on low heat for 10 minutes. Taste to see if you have got the right balance of spice, sweet and sour or adjust seasonings accordingly.
Remove from heat and garnish with yoghurt and coriander leaves.
Serve hot with steamed rice.