I may not completely understand why these little treats are called Whoopie Pies, since they seem to be much more of a cake than a pie, but I do know that they're delicious and extremely easy to make. There are several claims as to the actual origin and name of the beloved whoopie pie, which you can read about here. Ever since our little adventure to the Reading Terminal Market in Philadelphia, and our whoopie pies from The Flying Monkey, I knew I had to try making some at home. You should too.
There are a lot of different recipes available for whoopie pies. I tried several, and finally got to my version for these Chocolate Peanut Butter Whoopie Pies. I felt that these had the best chocolate flavor, and also were extremely nice and puffy. Using shortening makes the cakes puffier than if you used all butter or a butter-shortening mixture. Using half butter and half shortening works okay, but your cakes will be much flatter, looking more like a cookie than what I was going for.