Grind together coconut, black peppercorns and cumin seeds with 2-3 tbsp water to a smooth paste. Keep it side.
Cook together dates, ginger, green chilli, chilli powder, turmeric powder and salt with 1 cup water till dates softens.
Add the ground paste to cooked dates. Mix it well and let it simmer for 3-4 mins, till the raw smell goes.
Add the whisked yogurt gradually to the dish, stirring all the time. Once it's incororated, remove from fire.
Heat oil in a pan and add fenugreek and mustard seeds. Once it crackles, add dry red chilli and curry leaves. Pour it over the uogurt curry. Let it rest for 15 mins before serving with rice.