Pressure cook the toor dal with water, salt and turmeric for 3 or 4 whistles; open and mash well. If using a pot, cook the lentils with salt and turmeric and double quantity water till mushy.
Blend the coconut, cumin seeds, garlic and shallots into a fine paste.
To the cooked lentils, add the coconut paste and the kokum pieces and return to heat.
Add water to adjust consistency as required and season with salt. Bring to boil and then simmer for 5 minutes.
To prepare the tempering, heat oil in a pan, crackle the mustard seeds, cumin seeds, curry leaves, chillies and garlic. Saute till the garlic is lightly browned, switch off heat and add asafoetida.
6. Pour this over the hot dal and mix well.
Garnish with coriander leaves and serve hot with rice.