CAKE: Preheat oven to 350 degrees. Grease three 9-inch cake pans. Line each pan with parchment paper and grease the paper. Prepare cake as directed on the box. Bake 15-20 minutes or until the cakes springs back when touched. Allow to cool completely.
CHERRY FILLING: Drain cherries, reserving 1/2 cup juice. Combine reserved juice, cherries, granulated sugar and cornstarch in a 2 quart saucepan. Cook over low heat until thickened, stirring frequently. Remove from heat and stir in vanilla. Add a small amount of red gel food coloring to reach desired color. Cool filling before using.
In a small saucepan, over medium-low heat, dissolve gelatin in water, stirring constantly until the mixture becomes clear. Remove from heat and allow to cool, but do not let it set.
WHIPPED CREAM FROSTING: In the chilled bowl of a stand mixer, whip the heavy cream, confectioners' sugar and vanilla until soft peaks form. With the mixer on low, gradually add the dissolved gelatin mixture to the whipped cream.
Place one of the cake layers upside-down onto a decorative plate. Brush the top of the cake with the cherry juice. Next, spread enough whipped cream to cover the layer. Top with 1/3 of the cherry filling.
Set the second layer of cake upside-down on top and brush with cherry juice. Cover with whipped cream and 1/3 of the cherry filling.
Finally, place the third layer of cake upside-down on top and once again brush with the cherry juice. Cover with another layer of whipped cream, making a trench to hold the last 1/3 of the cherry filling. Decorate by piping whipped cream around the top edge of the cake. Pile shaved chocolate in the middle, if desired. Place cake in the refrigerator until ready to serve.
Cook's Note: I like the rustic look as shown in the photo, but there is enough whipped cream frosting to frost the sides. I prefer to serve the extra whipped cream on the side.
Simply spread frosting evenly around the sides of the cake and press the chocolate shavings into the sides of the cake, making sure to cover all spots.