Take the idli rice, urad dal, fenugreek seeds, and toor dal in a bowl.
Wash them together atleast 4 to 5 times until the water runs clear. Now add sufficient water and soak for atleast 5 to 6 hours.
Take the poha in a separate bowl and rinse it thoroughly. Now add sufficient water soak poha for one hour.
Grinding the ingredients
(Pic 1 ) Drain the water from the rice, dal mixture. In the blender (I used my Blendtec), add ¼ cup of water to the bottom. Then, add the drained rice, dal mixture.
(Pic 2) Grind it into a smooth batter by adding water as required. I added ¼ cup + 2 tbsp of water for this batch and used my smoothie setting to grind the batter. I ground it only for 40 seconds.
(Pic 3) Now add the drained poha. I did not transfer my rice mixture. I added the poha on top of it.
(Pic 4) Grind into a smooth batter by adding water as required. You might need little extra water for this batch. I added ½ cup + 2 tbsp of water, and you have to mix it in between using a silicone spatula. If not, the batter gets stuck in between the blades. Overall we need 1.5 to 2 cups of water to grind. I used 1.5 cups of water.
Fermenting the batter
Now transfer the ground batter into a bowl. Use ¼ cup of water to rinse the blender and add it to the batter. Add salt and mix well.
You can make the dosa right away, but I usually let it ferment for 5 to 8 hours. We love the sour fermented taste, so I let the batter sit. A slight fermentation like below is more than sufficient.
Preparing the dosa
Mix the batter well, and it should be in pouring consistency. If needed, add ¼ cup of water. I did add a little water.
(Pic 1)Heat a well seasoned cast-iron pan, and when it is hot, reduce the heat to medium-low. Take a spoon/ladle full of batter and pour it on the pan. Slightly spread it and do not make it too thin or spread as we do for regular dosa. Spread some oil around the edges; ½ tsp should be sufficient.
(Pic 2) Cover it with the lid and let the aval dosa cook in the steam. It usually takes about 50 to 60 seconds. Timing is approx, make sure the top side completely cooked.
(Pic 3)Here is the cooked dosa. As you can see, the color of the dosa is changed, and you can loosen the edges and remove the dosa from the pan - no need to flip and cook.
(Pic 4) As I mentioned before, flipping and cooking the dosa on both sides is optional. But no harm in doing that. Just to show the bottom of the dosa, I have flipped it here. Just cook for 15 to 20 seconds and remove from the pan.
Similarly, make the dosa with the remaining batter and serve hot with chutney or sambar.
Notes
I have always tried this dosa with toor dal. Toor dal adds nice texture and flavor. But you can experiment without it.
Fermentation is optional, and flipping and cooking the dosa on the other is also optional.
Aval dosa batter is for soft and spongy dosas. Cooking the dosa in steam yields soft dosa, and don't skip that. Do not overspread the dosa.