Are you familiar with Tandycakes? They are quite flat and the packaged ones made by TastyKake are round, fully encased in chocolate. A cake-like cookie with a layer of peanut butter surrounded by chocolate - fairly dense I guess you'd say. Well, I guess none of that makes sense since cookies have baking soda or powder in them too. All I can say is that it works and, no, the recipe does not call for either. But you should not expect to see a cake that resembles a sheet cake. I haven't made it in a while but I'd guess that it's no higher than 3/4". In fact I have a couple of cookie sheets that are a little bigger than the size called for and I always use the smaller 10x15" size. If I put it in the slightly bigger pan, it would be lucky to reach 1/2". Good luck and I hope you like it if you give it a whirl!