Measure Oats, both the dals, peanuts and rice into a flat plate. Take the ingredients into a mixer and grind to a fine powder. It can't be ground super fine, it will fine but a bit coarse powder.
Take this ground powder into a bowl. Add salt and around 2 cups of water first, using a whisk stir to a make batter. The batter thickens as it rests. So add 2 cups first then we will add more as required. Let this batter rests for 10 minutes.
While the batter rests, let us make the tempering. Heat a pan with oil, splutter mustard seeds, crackle cumin, add chopped chilies, ginger and curry leaves to it. Saute for a minute. Finally add shredded carrots to this and saute for another minute for the carrots to wilt a bit.
Add this tempering and chopped coriander leaves to the batter and mix well. Add another 1 cup of water to the batter and mix again. As i mentioned the batter thickens as it rests.
Heat a tava, i used my cast iron tava for making the adai. Pour a ladle of batter in the center and spread into a circle. Do not spread too thin, adai is usually thick.
Spread the batter a bit into a circle using the back of ladle. Make a hole in the center, this ensures even cooking. Drizzle a teaspoon of gingely oil all over and the edges. Cover and cook in a medium flame for a minute or two.
Open the cover, flip and cook the other side for another minute. Remove the adai to a serving plate.
Serve the adai warm with any side of your choice. I served with Peanut-coconut and sesame chutney.