To the soup base, add the reserved lentils. Almost all of the liquid, but not entirely, should have been absorbed during the cooking of the lentils. Therefore the lentils should not be dry but have just a bit of water to keep them loose. (If the lentils are too dry, add a bit more water) Bring the soup to a boil, reduce the heat to a simmer (212°F-100°C), and cover with a lid or tightly with aluminum foil for 45 minutes.
After 45 minutes, lift the lid and stir the soup. To this, add the butter and stir to incorporate. Once the butter has melted, stir in the coconut milk. Finally, add the asafetida (optional), stir to combine, and mix thoroughly.
Next, bump up the seasonings with lemon juice, Garam masala, Fenugreek, and minced cilantro.
Lastly, check the salt and pepper levels and, if desired, remove the whole ginger pieces (if any). Serve hot in bowls with garlic/cilantro Nann bread, and enjoy!