To make the batter – Wash and soak the both the rice, both the dals and methi seeds in enough water for about 6 hours or overnight. – When ready to grind, drain most of the water and grind it in wet grinder to a smooth batter. Make sure that the batter is on the thicker side, like idli batter as that makes the oothappam fluffy and crisp. You could also grind the batter in blender in batches.
– Remove the batter in a large container. Add salt needed and mix well using your hands. My mother always says that mixing the batter with hands help promote the fermentation process. Make sure that the container is at least twice as big as the amount of batter as the batter will double in volume when fermented. Depending on how warm it is, it might take anywhere from 12 to 24 hours for the batter to ferment. It took about 24 hours for mine to ferment.
– Heat a griddle / tawa and pour couple of ladleful of batter. Spread it into a thick circle. Make sure that you spread the oothappam batter in a thick circle and don’t make them thin. Also keep the flame in medium heat when making the oothappam as we want to allow them to cook on the inside as well. – Sprinkle the chopped onions, cilantro, green chilies and carrots evenly over the surface of the batter. Pour a spoonful of oil around the oothappam and let it cook for about a minute or until it is golden brown.