All of the above...I've tried Presto, Swans and Softasilk, and Softasilk is by far the lightest...It never fails to deliver a light and fluffy cake; of course other factors contribute to that as well. I'm one of those who prefer to sift atleast once...It won't hurt

You can also substitute it when recipe calls for regular flour...Just measure and add 2 tablespoons per cup. I goes a long way.
