<<Disclaimer: Verify this information before applying it to your situation.>>

I would like to thank Ann (the orginal poster of this fantastic info) and K.
Ann recommended a straight substitution of cornstarch for all purpose.  Last
night, I could not wait.  I pulled every cookbook from my cabinets and
finally found it.  When I get the "cooking bug"  there is no stopping me.
When a recipe calls for CAKE FLOUR and all you have is ap flour; you need to
REMOVE 2T OF AP FLOUR PER EVERY CUP.  I made a 2 layer carrot cake last
night.  It turned out very well, great flavor, light, and moist.  I
converted the recipe from ap flour to cake flour and then again to
cornstarch.  The recipe called for 2C of ap flour.  I used 2C plus 4T
cornstarch.  When I baked a butter poundcake a few days ago, I subbed
cornstarch for cake flour and had no problems.  It tasted great!  As Ann
recommended, cover/wrap the cake well.  These cakes tend to dry out quicker
than wheat ones, however, no one will know they are not made from "regular"
flour.

        Thanks everyone,
        Rhonda Young in NV