Preheat the oven to 350°F and line 2 cookie sheets with parchment paper.
In a microwave safe bowl, combine the butter and finely chopped chocolate. Microwave in 15 second increments, stirring well between each until the chocolate is completely smooth and melted. Do not overheat the chocolate as this can burn it. Set aside.
In a stand mixer fit with the whisk attachment, combine the eggs and sugars. Beat on high speed until light and pale yellow in color, about 3 minutes.
With the mixer on low, slowly add in the chocolate and butter mixture, mixing until completely homogenous. Stop the mixer.
Add the peppermint and vanilla extract and mix to combine.
Add the flour, cocoa powder, salt, and espresso powder. Mix until combined. The dough will be soft.
To get the distinct glossy tops, do not let the dough sit! As soon as the dough is mixed, use a standard size cookie scoop to scoop out the cookies onto the prepared cookie sheets, dropped about 2 inches apart. Bake for 10 minutes or until the cookies have crackled and are set on the edges, but still gooey in the middle.
As soon as the cookies come out of the oven top with crushed up candy canes.