The speckly finish on top is created by spraying it with chocolate, which is no small endeavor and I would not recommend it for home cooks - it is noisy and messy and requires a lot of setup!
I also sprayed the top of my passionfruit mousse cake:
As you can see I had some fun with piped chocolate on both cakes... BUT WAIT, THERE'S MORE!
We made some baumkuchen, too. Those are both mine - the first is filled with orange yogurt cream, the second with white chocolate mousse. Yes, confusing, the mousse one is the one with the oranges, I know. The wood-veneer pattern comes from the cake being baked in very thin layers, then sliced like bacon so the layers show when you arrange the surface. It was just like pattern blocks in Kindergarten again. So much fun!