As I mentioned in the intro, whoopies can be a fickle cookie.  To get that cakey texture you want from a classic whoopie pie, you have to have a softer batter than a traditional cookie. That can mean you’ll get a lot more spread, and they won’t hold their shape well.  This recipe has been developed to strike the perfect balance between a well-shaped cookie and a fluffy cake batter typically baked in a pan, so you can enjoy the best of both worlds!