Enjoy a naturally sweetened alternative to traditional chocolate cake. Pureed prunes are combined with melted chocolate, vanilla, and hazelnuts to form the base of this Bittersweet Chocolate Cake with Prune Puree and Hazelnuts. The cake batter is further sweetened with maple sugar before being combined with whipped eggs whites. Serve the finished cake with a dusting of powdered sugar or a dollop of whipped cream alongside some berries for the perfect chocolaty dessert.