Mix baking soda and cream of tartar together in a small bowl.
If you want a finer texture, add in the cornstarch and mix together.
Store the mixture in an air-tight container.
Interesting Facts
This homemade baking powder substitute is a great way to replace store-bought baking powder in any recipe.
It is important to make sure that the baking soda and cream of tartar are fresh, as old baking powder can cause baked goods to become tough or not rise properly.
The cornstarch is added to help with the texture of the finished product, but it is not necessary.