I have always had it in my head that cake flour is waaay better for making cakes than AP (all purpose) flour. This ensured a better rise and less of a chance of falling. Yadda yadda yadda. I felt like I couldn't make from scratch cakes because I wasn't going to throw down for the more pricey cake flour. In turn I wasn't able to produce spectacular cakes. I was wrong! (Notice the past tense. I don't like being wrong for very long. I am no longer wrong. Wink wink.)
From Your Kitchen Cake Flour
Go get it:
1 cup AP flour minus 2 T
2 T corn starch
Go make it:
Mix flour and corn starch. Sift. Ta da. For realz. This will produce one cup of cake flour. Double, triple or quadruple to your heart's content.
In a pinch you can also use a low protein flour in place of cake flour. For instance self rising flour. That is if you have self rising flour on hand. Cheapo here doesn't usually have self rising flours either. You should just omit the salt and leaveaners. Who knew?!