This thoroughly adult cake combines roasted hazelnuts with rich cocoa for a love letter disguised as a layer cake. My Taster says it’s the best cake I’ve ever made. You can make it too! This cake is based on my Chocolate Celebration Cake, but with hazelnut flour in the cake itself and NewTella hazelnut spread in the my Chocolate Buttercream Frosting. Adding the hazelnut flour amps up the flavor and sophistication of this cake. The NewTella in the frosting brings on the full swoon, but is optional. Make it as a sheet cake if you want to seduce (or at least delight) a crowd.