I made one a while back, also for a kid birthday. Looked at that recipe, but ganache is not in my (or kid’s) experience of Black Forest cake, so I did not follow it and kept looking for versions rather than a singular recipe, mostly European recipes rather than American.
What I ultimately did was try to replicate what we have eaten as Black Forest cake using components I was comfortable with — main parts were the shortcrust pastry base (which I looked up) and the chocolate cake layers, for which I used my standard recipe for birthday cakes (crazy cake / amazon cake).
I did not stabilize the whipped cream (we had vegetarians so no gelatin, and I was concerned about cornstarch altering the flavor).
Kid was happy. Pics of the cake are on WFD.
