So I have this rather strange dilemma. I make a rather wonderful tandy cake, ya know the vanilla cake with peanut butter covered with chocolate? We tweaked it, actually, to use chunky peanut butter, and it made it even better, in our opinion. However, a friend asked if instead of white cake bottom, if it could be chocolate. I've read where adding cocoa could do the trick...but I'm not sure just how much to add to experiment with this concept. He absolutely loves chocolate, so he would like a chocolate cake with peanut butter, topped with chocolate. Any suggestions on doing this? Using a basic tandy cake recipe, easily available on the internet. Let me know if anyone has any ideas! Thank you so much!