Take rice and dal in a bowl and wash them well, add fenugreek seeds and soak them for 4 hours. Now drain and add it to a grinder or blender and puree till smooth.
Take it in a large container, add salt and mix well. Leave to ferment for atleast 8 hours or overnight.
Now heat oil in a pan, add mustard and urad dal and let them sizzle.
Add asafoetida and curry leaves and let them sizzle.
Add in green chillies, ginger and onions and saute for few mins. Add salt and mix well.
Add this into the batter and mix well.
Heat a paniyaram pan with some oil, pour ladleful of batter in each hole and cover and cook for 2 to 3 mins.