The mask and violin are fondant-covered, carved cake. I made this fairly shortly after the Kick-Bass Cake, and was continuing to experiment with the idea of a carved, 3D cake pieces. As a result, both mask and violin are considerably thicker than they would be realistically (much, much thicker)...but hey, it means more cake to eat!
(Silver linings, I tell you, they're everywhere.
Detail shots of the violin and mask to follow shortly...
The cake itself is chocolate-mocha, with chocolate-khalua buttercream frosting, nom nom nom. There are also blue "ribbons" of fondant around the edge that you can't really see in this shot, ah well.