Cake Flour vs. All-Purpose Flour

Today is Howard's birthday! Also George Eliot's birthday (my new project has begun: chronicling the experience of reading Middlemarch: From Here to Middlemarch). We woke up and cuddled with Baudelaire for a bit, and then walked to the grocery store. It's Howard's favorite kind of day: the sky is a solid gray and it's chilly, but not too cold. I made pancakes from scratch and sausage. Howard asked for a chocolate cake (which I made with Aaron in May and that journeyed across many neighborhoods afterwards) and so after breakfast I made him a chocolate cake.

My recipe called for cake flour, which I'm out of. Which led me to ask: What's the difference between cake flour and all-purpose flour, and are they interchangeable? What I learned today is that cake flour has less protein than all-purpose flour, and helps to make a cake light and fluffy while retaining its shape, but isn't tough or dense. 

If you are like me, and habitually forget important ingredients in your recipes, it's valuable to know how to make substitutions. My most frequent Google search term is: "what's a substitute for _______?" So when you are making a dessert that calls for cake flour and all you have is all-purpose, here's what you can do:

For every cup of flour your recipe calls for, remove two tablespoons and replace it in your flour bag, or use it to dust the greased pans, like I did. Replace it with two tablespoons of corn starch, and sift together five times. 

If you are like me, and don't have a sifter, whisk together multiple times with a fork. I hope that works, because that's what I did. I tried and make sure it got lots of air. 

When we remove some of the flour, we are cutting out some of the gluten and replacing it with an agent that inhibits gluten development, leaving the cake tender. Read more about it on Joy the Baker, which is where I learned about it.

Here are the cakes cooling:

I will add photos of the finished project later!

UPDATE 12/2/14: Finally, pictures. Howard's birthday cake with wrapped presents: