Hi Elizabeth. Wasn't sure how to reply to the filling question and not sure what your exactly looking for chocolate cookie filling. I recently did a Oreo Cookies N Cream filling. It's really easy you can use Bettercream and add a box of dry Oreo Cookies N Cream pudding or use heavy whipping cream and the pudding you will have to tweak it to your own taste I personally don't like overly sweet fillings or frosting. Make sure you use a thick dam. HTH.