Preheat oven to 350F and line 2 baking sheets with parchment paper.
Cream together the butter and both sugars using an electric mixer until light and fluffy (about 3-5 minutes).
Add egg, vanilla extract, and peppermint extract and mix again until fully combined.
In a separate bowl, add flour and sifted cocoa powder. Then add baking soda and whisk until fully combined.
Add dry ingredients to wet ingredients and mix well until fully incorporated. The dough should be thick and slightly sticky.
Add chocolate chips and mix well.
Roll cookie dough into 16 1.5” balls and press down slightly with your palm to partially flatten.
Bake for 10 minutes.
Remove from oven and sprinkle with crushed candy canes right away so they stick to the warm cookies.