Preheat your oven to 350°F.
Combine the Devil's food cake mix, water, vegetable oil, eggs, and pudding mix in a large mixer bowl. Beat on medium until well blended. Make 18 evenly sized scoopfuls of batter on Silpat-lined baking sheets. Form a round shape.
Bake for 12-15 minutes, depending on the size of the batter circles. Let fully cool before decorating.
Beat butter until very creamy. Slowly add in powdered sugar and continue beating until combined. Add vanilla and fluff. Mix in cherry juice adding more if desired. Carefully mix in chopped cherries.
Frost flat side of one whoopie pie. Place another whoopie pie, flat side down on top to the filling, pressing down lightly.
Wrap whoopie pies individually in plastic wrap. Store in the refrigerator.