What the heck is cake flour anyway?

I know it's happened to everyone out there...well, everyone that bakes that is. You're happily following a recipe and you come across the ingredient cake flour. You think to yourself, "What the heck is cake flour anyway?" as you pour in your all-purpose flour. Does it really make a difference? Honestly, I have no idea! Wish I could help you out. Well, I actually can help you out if you're really curious. In this month's Cooks Illustrated magazine it states: "With just 6 to 8 percent protein, cake flour imparts a more tender, delicate texture to baked goods than all-purpose. Here's how to make an approximation.

2 tablespoons cornstarch + 7/8 cup all-purpose flour = 1 cup cake flour

Happy Baking!