When you choose your cake mix just purchase a frosting that you would frost that flavor cake with.
Prepare cake according to directions on the box. Allow to cool and then crumble entire cake in a mixing bowl.
Mix in the entire can of frosting and mix with your hands like you would if you were making meatballs.
Roll into bitesize balls and place in the fridge for 30 minutes to chill and firm.
While you are chilling your cake balls you can melt both white and chocolate bark and put in ziploc baggies. Cut a tiny hole in the corner of your baggie.
When you cake balls are firm simply drizzle your white and chocolate bark over them as you prefer.
*Hint - common combinations can be red velvet cake and cream cheese frosting, chocolater and chocolate, carrot cake and cream cheese, lemon and vanilla... the choices are tremendous. I also love to do an entire tray of chocolate and roll some in nuts, some in coconut, etc. These are fantatic!!!