If you let sit overnight:

1. When you are ready to cook the Injera, add 1/4 cup warm water, the two salts and mix well.
2. Proceed to cooking instructions below.

If you let sit for 1 hour:

1. When you are ready to cook the Injera, add 1/4 cup warm water, the two salts, and vinegar and mix well.
2. Sprinkle the baking powder and whisk.
3. Proceed to cooking instructions below.

To cook the injera:

1. Heat a large non-stick pan (12") on high heat until hot.
2. Drizzle a teaspoon of oil. Spread the oil using a paper napkin to form a thin oil layer on all of the pan.
3. To start, pour 2-3 Tablespoons of the batter and make the flatbread (it is recommended to make a smaller flatbread to begin with to let the pan heat well and also get a feel for how the batter moves). See "Notes" below. 
4. Pour 1/3 to 1/2 cup of the batter on the hot pan.
5. You can either pour the batter in circles or pour all of it and then move the pan to spread it around. See pictures below.
6. Once spread, wait for a few bubbles to appear then cover the pan with a lid to steam the injera for a minute or so.
7. Remove lid and let cook until the center is set and not wet and the edges start to pull away (3-5 min).
8. Remove the injera and let cool. The edges might feel crisp when you take it off heat, but will soften once cool.