Whisk one cup of plain yogurt with two cups of water until it's smooth and lump-free, creating a thin, buttermilk-like consistency.
Heat one tablespoon of coconut oil or ghee in a pan over medium heat.
Add one teaspoon of mustard seeds, and when they start to splutter, add half a teaspoon of cumin seeds, a quarter teaspoon of fenugreek seeds, and two to three dried red chilies.
Add a small amount of asafoetida. Add one sprig of curry leaves, one slit green chili, and one inch of finely chopped ginger (if using), and sauté for a few seconds.
Reduce the heat to low, and pour the yogurt mixture into the pan.
Add a quarter teaspoon of turmeric powder and salt to taste.
Gently simmer the Mor Kulambu over low heat, ensuring it doesn't boil to prevent curdling, and stir occasionally.
If using, add a quarter cup of grated coconut during the last few minutes of simmering.
Once heated through and slightly thickened, remove the Mor Kulambu from the heat.
Serve hot with rice.
