Sponge Dosa

Rinse the Idli rice thoroughly under running water until the water runs clear. In a separate bowl, rinse the Urad dal and Fenugreek seeds together.

Soak the Idli rice in one bowl with sufficient water, and the Urad dal and Fenugreek seeds in another bowl with sufficient water, for at least 6 hours or preferably overnight.

Drain the soaked Urad dal and Fenugreek seeds. Grind them in a wet grinder or high-speed blender with approximately 100g of fresh water, adding more as needed, until you achieve a very smooth, fluffy batter. Transfer this batter to a large mixing bowl.