Is cake flour plain or self raising?

Here's why:

* Cake flour has a lower protein content than all-purpose flour, resulting in a softer, more tender crumb.

* Self-raising flour already contains baking powder which is not needed in cakes, as they often require a separate leavening agent like baking powder or soda.

So, if you need cake flour for a recipe, be sure to use plain flour and adjust the recipe accordingly (adding baking powder and reducing the liquid slightly).