Being a german, I think I can give some german background info, just for fun.
So "Baumkuchen" tree-cake gets it's name from the way it is baked. Basically you apply a small layer of dough in the form, backe it and apply another layer after a some time. The parts that where exposed to the hot air for a while are more brown than the rest of the cake. So if you slice it and look at it from the side, it looks a bit like wood grain, thus giving it the name.
Also... I am pretty happy to read storyes where germans are part of the good guys. No seriously, if you pay attention, you will be surprised in how many manga germans are bad guys. I mean overall it is more funny than bothering.