For the Batter

Take a bowl and add the oats, rice, dal and the fenugreek seeds. Wash everything in water. Add three cups of water and the aval / poha. Soak everything for two hours.
After soaking add the salt and grind everything to a smooth batter. Use the soaking water for grinding.
Ferment the batter for 6-12 hours. If it’s summer, it will take about 6-8 hours. In winter, it will take a longer time. If you live in a very cold place, leave your batter in some place warm. Leaving your batter inside your oven with the pilot light on works great if you live abroad and your place is cold. Once the time is up, the batter should have increased in volume. Take a ladle and mix it well. Your batter is ready. Refrigerate the batter after fermentation. Use within 2-3 days.

To make dosai

Heat the dosai griddle until medium-hot. Add 1/3 cup batter and swirl to cover the dosai griddle. Sprinkle 1/2 teaspoon of Indian sesame oil/peanut oil or ghee. Cook until the underside of the dosai is golden brown, about a minute. Flip once. Cook for a few seconds. Remove dosai from the griddle and repeat with the remaining batter. Serve hot.