I love using box mixes for my Cake Puck cores because they have great flavor and its fast and easy! I have adapted the recipe to be a little more dry.
I know, I know.... the best cakes are nice and moist! But for your CP cores you want to be able to add lots of delicious frosting to your cake crumbs, so the goal here is flavor without the density of a moist cake.
Any brand of cake mix will do so use your favorite!
Chocolate Box Mix Recipe
one 15.25 chocolate cake mix
one cup water
1/3 cup oil
2 TBL vanilla extract