I have a batch of left over reg. buttercream from my last cake which was 2 days ago. How can I convert that buttercream into chocolate buttercream? I will be using it as a filling for this next cake.
Just add cocoa powder or melted unsweetened chocolate to it. If you use cocoa remember to add milk or water a little at a time to bring it to the consistency you want. And sift your cocoa.