Soak the Ingredients: In a large bowl, combine the raw rice, urad dal, and fenugreek seeds. Rinse them thoroughly under cold running water until the water runs clear. Then, add enough fresh water to cover them by at least 2-3 inches and let them soak for 4-6 hours. You'll notice the grains plump up significantly, becoming softer to the touch.

Grind to a Smooth Batter: Drain the soaked ingredients and transfer them to a high-speed blender or a wet grinder. Add just enough fresh water (start with about 150ml) to help the blades move, and grind until you achieve a very smooth, creamy batter. It should be the consistency of thick pancake batter, with no discernible graininess when you rub a little between your fingers. You might hear a gentle whirring sound as the ingredients break down into a fine paste.

Ferment the Batter: Pour the ground batter into a large, clean bowl. Add the salt and mix well with your hands – the warmth from your hand can aid fermentation. Cover the bowl loosely with a lid or a clean cloth and leave it in a warm spot in your kitchen for 12-18 hours. You'll know it’s ready when the batter has visibly risen, becoming airy and bubbly, and you might detect a pleasant, slightly sour aroma.