In a blender mix the water, all-purpose flour, Teff flour, honey, yeast, baking powder, and salt. Blend until you have a smooth batter.
The batter should be a little thicker than crepe batter, but not as thick as pancake batter. If you need it thinner, add water: if thicker, add more all-purpose flour.
Once you have your batter, place at room temperature for ~2 hours. Let it sit until you have a very bubbly froothy batter.
Once the batter has fermented, add 1 TBSP apple cider vinegar and mix well.
Heat a crepe pan on Medium Low (depending on your range) and spray with cooking spray.
When the pan is hot enough, apply pour 4 ounces of batter onto the pan (I use a 2 ounce laddel, using 4 ounces total). Spread with the crepe spreader to a nice round shape. Brown one side then flip the Injera and brown the other. Stack the Ethiopian flat bread until cool if you are not going to use them all, and freeze with a piece of parchment between each.
Notes
It is important to make sure that the batter is not too thick or too thin. Try to end up with a batter a little thicker than crepe batter but thinner than pancake batter.