This Black Forest Spiral Gateau gives a German classic an elegant, rolled twist. A chocolate Swiss roll forms the beautiful spiral border, while the interior consists of layers of delicate cocoa sponge, homemade Sour Cherry Curd, airy Mascarpone cream, and juicy sour cherries. Finished with whipped cream, fresh cherries, and dark chocolate shavings, this elegant cake is a real summer showstopper.