Dosa batter in a mixie! You can make about 20 dosas with this batter.
1. Wash and soak the idli rice with water. Wash and soak whole urad dal with fenugreek seeds, poha separately with enough water. You can use the same water to grind as well. Let it soak for about 6 hours.
2. Take the biggest mixie jar you have and grind the idli rice first. If you cannot fit all the rice at once do it half and half. I totally added a little more than two and half cup water. You can divide the water depending on how many batches of rice you can fit in your mixie. It is ok if it?s not a smooth texture as it will be have minute crystals. Once you have finished grinding to the mentioned texture, transfer it to a bowl. Take a big one as the batter increases in size after fermentation.
3. Next put the urad dal in the mixie. It is not necessary to wash the mixie when we start this step as we are going to mix the both in the end. Start by adding a little water and you can grind to a silky smooth texture. I added almost two cups of water.
4. Once done, add the urad dal mixture to the ground rice. Add salt to the batter and mix it with your hand. It is important to mix it with your hand as your body heat is supposed help ferment the batter. Now the time to leave the batter to ferment really depends on a lot of factors. Your room temperature, outside temperature and quality of ingredients. The city I come from India is very hot and my mom's batter doubles in size when she leaves it to ferment overnight. I currently live in a city when it is cold most of the year. I usually leave it inside the oven with light on for twelve hours (Make sure not to switch on the oven). Depending on where you live, this might be something you try a couple of times to see what works for you.
5. Time to make the dosa! Take a ladle full of batter and pour it on the hot tava. Spread it circularly to form a thin layer and add a few drops of ghee/oil. Once you see the other side is turning brown, flip the dosa. Let it cook for about 30 seconds. Time to serve it hot with sambhar, chutney or chutney podu.