Preheat oven to 350ºF. Mix a double batch of Only Oats Decadent Chocolate Muffin Mix as per package instructions. Pour batter into two 8 or 9 inch cake pans. Bake for 30-35 minutes or until centre springs back. Cool and cut both cakes in half horizontally. Whip 2 cups of whipping cream sweetened with 1/4 cup sugar. Layer the slices on a serving plate, spreading the whipped cream and a gluten-free cherry pie filling between each layer. Begin with a bottom layer, then the two top layers, finishing with the smooth side of a bottom layer facing up. Decorate top with whipped cream swirls, chocolate covered cherries, and chocolate shavings.