Rinse the quinoa and rice under running water until water turns clear and then soak quinoa and rice together in enough water (around 2.5 cups) for around 6 hours.Similarly, rinse urad dal until running water until water turns clear and then soak in enough water (around 2 cups) with 1 teaspoon methi seeds for 6 hours.
After 6 hours, drain water in which quinoa and rice were soaked using a strainer. Then transfer the drained quinoa and rice to a high speed blender (I used Blendtec).Add around 1 cup (8 oz/240 ml) cold water and grind to a smooth paste.
Transfer the ground quinoa and rice to the steel pot of the Instant Pot (or to any other big bowl if not using the Instant Pot).
Similarly drain the dal and methi seeds using a strainer and then transfer to a blender.Grind the dal to a smooth paste using around 1/2 cup (4 oz/120 ml) + 2-4 tablespoons (30-60 ml) cold water as needed. I suggest you add 1/2 cup +2 tablespoons initially and add more while mixing the batter if it looks too thick.
Transfer it to same pot as the ground quinoa and rice. Add 1 teaspoon sendha namak, do not regular iodine salt here.
Now, using clean hands, mix the the both the batters along with the salt. Mix really well using your hands for 2 minutes, this helps in fermentation.PS: If you live in a warm place, you might not need to add salt at this point.
The consistency of the batter should be free flowing. It should not be runny but it should not be super thick either. If it doesn't have a flowing consistency, you can add more water at this point.
Now cover the pot with a glass lid (if using Instant Pot) or with any other lid if using regular container. Remember to use a glass lid if using Instant Pot .If you use regular Instant Pot lid, the batter might overflow and lock the lid, so use a glass lid.Place the pot back into the Instant Pot. Press the Yogurt button. Increase the time to 12 to 14 hours. The time will depend on where you live. It takes around 12 hours to ferment here in summers and around 14 in winters using the IP.If not using an Instant Pot, cover the container and place in an oven with lights on (especially if you live in a cold place). If you live in a very warm place, then simply keep the batter on the counter to ferment.
After 12 hours, my batter was fermented. It had that fermentation smell and it was frothy on top. It had also increased in volume.
If you want to check whether your batter has fermented or not, simply take a bowl of water and drop some batter into it. If it floats, it means the batter is fermented and ready to use.
To make idlis, grease idli plates with little oil. I used Instant Pot to steam the idlis but you can use a regular steamer as well. Fill the idli plates with the batter. While you are filling the idli plates, place 1 to 1.5 cups water in the pot and press saute button for the water to heat up.
Place the idli stand in the Instant Pot. Close lid and press the steam button and set time to 13 minutes with pressure valve in venting position. The instant pot does not count time in venting position so use an external timer. The idlis will be done in 13-14 minutes after you place them in the pot.If not using an Instant Pot, steam using an steamer for 10-15 minutes or until a knife inserted comes out clean.Take the stand out of the Instant Pot and let idlis cool for few minutes and then carefully take them out.
Serve quinoa idli with sambar and coconut chutney!
Please read all the tips in the main post before making the recipe, they will definitely help.
Remember to not over-ferment the batter. If that happens, the idlis will taste sour.