Soak foxtail millet, Idly rice, Black gram + Fenugreek seed in water separately for 2 to 3 hours.
Grind soaked black gram + fenugreek seeds into a fine thick batter by adding water as needed in a mixer or grinder.
Grind soaked foxtail millet, idly rice into a fine thick batter by adding water as needed in a mixer or grinder.
Now mix these two batter well by adding salt as needed. NOTE: add water if needed to get the batter consistency.
Keep this 6 to 8 hours so the batter ferments.
-- Making kuzhi paniyaram --
In a pan heat oil. Now add mustard seeds, split black gram. Once the mustard seeds stop splattering. Add onion, green chili, curry leaves and sauté for a 1 to 2 minutes. Now add this to the batter and mix well.