Preheat the oven to 375°F and line a baking sheet with parchment paper.
In a medium bowl, combine flour, cocoa powder, baking soda and salt. Set aside.
In a large bowl, whisk together butter and sugars.
Mix in the egg, vanilla extract, espresso powder and peppermint extract.
Sift in the flour mixture. Mix until just combined.
Fold in the chocolate chips until just combined.
Scoop 1/4 cup cookies and flatten to 1 inch thick disks. Transfer to the baking sheet, leaving 2 inches (5cm) between each cookie.
Bake for 8-10 minutes, until the center is no longer looks shiny and wet. Cool.
Decorate with white chocolate and crushed candy canes.