Can cake flour be used in place of all purpose flour?

I am preparing the pastry dough for some pecan tarts. I found an article that suggested adding an additional 2 tablespoons of cake flour to equal 1 cup of all purpose flour. The dough is chilling, I'll find out tomorrow how well it bakes:)

What is it that you're making? Sometimes you can, other times it's better not to substitute it. Please, let us know! ;o)