Well despite following the recipe in Brewing Classic styles, - using the puree/cocoa powder, I got very little chocolate or cherry flavo. I added more cocoa powder and 3.3# of puree in secondary. Nothing. So have a fruit fortified, good for our health porter. Not bad, and I won't get scurvy!.
I'm going to play around with some choc/cherry extracts, but leery as they can make stuff taste like cough syrup.
FolkI know used maraschino cherry juice, grenadine, and creme de cocoa to get both elements in their stout.
I'm doing a re-brew after some experimenting and will report back in.