Add fresh coconut, roasted Bengal gram, yogurt, green chilies, mint leaves, ginger, cilantro, tamarind paste, and salt to a blender along with water.
Grind to a smooth paste.
Heat oil. Add mustard seeds and white urad dal (split and skinned black lentils).
Add dry red chilies (remove the stalk), curry leaves, and asafoetida and fry for 2-3 seconds.
Pour the tempering over the chutney and mix well. Serve at room temperature.