Preheat oven to 350°F. Lightly spray a 9x13 baking dish with baking spray.

Remove cherries from jar, reserving juice. Slice 15 cherries and keep remaining cherries for garnish.

In a large bowl, mix cake mix and Cherry Dr Pepper until just combined.

Stir in sliced cherries gently.

Pour batter into prepared dish and bake for 28 minutes until a toothpick comes out clean. Cool completely.

In a mixer, beat softened butter and 1/4 cup cherry juice until smooth. Gradually add powdered sugar until frosting consistency is reached.

Spread frosting evenly over cooled cake.

Score the cake into individual servings. Garnish each serving with a cherry with stem.

Refrigerate cake for 30 minutes to set frosting. Top with chocolate shavings before serving.