TO MAKE CAKEBALLS: Crumble cooled cake into large bowl. With the back of a spoon, mix together cake crumbles, frosting and 1/2 cup apple pie filling, until a thick dough consistency forms. Shape into evenly sized cake balls and cool 1-2 hours in the fridge or 20 minutes in the freezer. I use a small cookie scoop for the balls and roll in my hands to get them even. Once the balls have chilled, dip into white or dark melting chocolate. You can use chocolate, almond bark, or I prefer, Wilton candy melts for coating.