Preheat oven to 350°F. Line two baking sheets with parchment paper or Silpat mats.
In the bowl of a stand mixer fitted with the paddle attachment (or a large bowl if using a hand mixer) cream together the butter and sugars. Add the eggs, vanilla and mint extracts, and mix until smooth.
In a separate bowl whisk together the flour, cocoa, baking soda, baking powder, and salt. Slowly pour the flour mixture into the sugar mixture and mix on low until just combined. Stir in the chocolate and mint chips and then refrigerate the dough for about 15 minutes.
Use a medium cookie scoop or tablespoon to scoop the dough onto the prepared baking sheets, about 2 inches apart. Bake for 8-10 minutes until edges are firm and center is still slightly soft. If you wish to decorate with chocolate mint candies, put them on while the cookies are still warm.
Allow to cool on the pans for about 5 minutes before moving to wire rack to cool completely (or eat them while they're warm and ooey gooey delicious!)