Prepare the cake according to box directions, bake, and set aside to cool. Let cool until room temperature.
Once the cake is cool, transfer it over to a large mixing bowl and crumble the cake into large pieces.
In a medium mixing bowl beat the butter and powdered sugar until fluffy, about 1-2 minutes. Add in cocoa powder and peppermint extract and mix until combined.
Add the frosting to the crumbled cake pieces and mix with rubber spatula until just combined.
Shape the mixture into medium-sized balls, about 1 ½ tbsp worth. Chill in the fridge for at least 2 hours.
In a microwave safe bowl, melt the chocolate chips and heavy cream until smooth and silky once stirred.
Immediately start coating the cold cake pops in the chocolate ganache and place them on a cookie sheet lined with wax paper or parchment paper. After each individual coating, top with a pinch of the crushed peppermint candies so that they stick to the chocolate ganache. After all of the pops are coated and topped with peppermint candies, place them in the refrigerator until the ganache has hardened.
Keep them stored in the refrigerator in an airtight container for up to 5 days.