In a medium bowl, combine the flour, cocoa powder, baking soda and salt with a whisk. Set aside.

In the bowl of a stand mixer, cream together the white sugar, brown sugar and melted butter on high. When that is well-mixed, reduce the speed to low and add the egg, vanilla extract and peppermint extract. When this is well combined, slowly add the set-aside flour mixture until just combined. Then fold in the chocolate chips using a spatula.

Using a tablespoon measuring spoon, measure out the dough. Place the cookie dough one inch apart on the prepared baking sheets.

Bake for 9-10 minutes, or until the cookie edges look browner than the dough. Remove from the oven. Immediately press the top of each cookie with a spoon or the flat side of a knife to flatten the cookie, just a little, and sprinkle the top of each cookie with a little bit of crushed candy cane. Let cool on baking sheet for 5 minutes, then let them finish cooling on a baking rack.