Prep: In a large bowl, add all ingredients listed under 'Idli Mix', and mix well. Keep aside for 15 minutes while you prep the instant pot and molds. Add 2 cups of water in the inner pot and turn on SAUTE (high), so that the water comes up to a boil. Grease the silicone molds or Idli steamer lightly, using PAM cooking spray or ghee. Keep aside.
Prepare tempering: Heat a fry-pan on medium-high heat. Add all ingredients listed under 'Tempering'. Wait for the mustard seeds to pop, and urad dal to turn golden in color. Remove from heat and mix in the idli batter.
Cook idli: Add Eno fruit salt in the batter and mix it in gently. Don't over-mix the batter. Fill up the silicone molds about ¾th of the way. Place the silicone tray on a trivet and lower it in the instant pot. At this point the water will be boiling, so be careful while doing that. Carefully stack the second mold on top of the first one, placing it such that the cavities DON'T overlap. If using Idli stand, fill up the idli molds ¾ of the way and follow the same process. Close the lid. Set vent at VENTING position. Press STEAM for 12 minutes. The Instant Pot doesn't count down the timer in STEAM mode, so set an external timer (oven, microwave, siri, alexa).
Idli is done: When the timer is done, let the pin drop before opening the lid, takes about 30 seconds or so. Carefully open lid and remove the silicone molds or idli stand. Let the idlis cool for 2-3 minutes before popping them out of the mold. If using the silicone molds, they slip right out when you invert the mold and push gently. Serve idli warm, with your favorite side of chutney. We love ours with homemade cilantro-mint chutney and ginger chutney.
Notes
Eno Fruit Salt: If you cannot find this in-store or online, substitute it with ½ teaspoon baking soda + ½ teaspoon citric acid.
Rava: Look for coarse rava (suji) for best results. If you like to save time, buy roasted rava.
Yogurt: Use regular plain yogurt for this recipe. 2% or full-fat, both work great. I don't recommend using Greek yogurt in this recipe.
Make it nut-free: Skip the cashews to make this recipe 100% nut-free.
Note: The nutrition facts below are my estimates. If you follow any diet plan, I recommend cross-checking with your preferred nutrition calculator.