Night before you want to make Injera: Mix all the ingredients well in a bowl; loosely cover with a plastic wrap or kitchen towel and set aside at room temperature for 12-24 hours (I made Injera for dinner the next day, so the batter sat for almost 20-22 hours).
When ready to make the crepes: Preheat a 10” nonstick skillet on medium heat. Mix the batter thoroughly.
Use cooking spray to lightly grease the pan; pour about ⅓ – ½ cup of batter into pan; immediately twirl the pan to evenly distribute the batter. Let cook for 1-2 minutes until bubbles rise to the surface; COVER the pan with a lid and let the crepe steam for 2-3 minutes.
At this stage, the injera should be completely cooked on the underside; the top should be set and firm and should be pulling away from the sides. Cooking the other side is optional; I cooked the second side for about 30 seconds.