In the bowl of a stand mixer fitted with the paddle attachment, or in a large mixing bowl using an electric mixer, beat the butter and sugars until light and fluffy. Make sure that your butter is at room temperature and beat it on a medium speed for about 5 minutes.

Next, add the egg, egg yolk, vanilla and peppermint extracts to the bowl. Beat on medium speed for another 2-3 minutes, or until creamy.

In a separate bowl, whisk together the flour, cocoa powder, baking soda, espresso powder, and salt.  

Add the flour mixture into the creamed butter mixture and beat speed until there are no more dry spots. Once the cookie dough comes together, add 1 cup chocolate chips and continue beating on low until they are evenly distributed.

Cover the cookie dough with plastic wrap and chill. For the best tasting cookies, you will want to chill the cookie overnight, but if you are in a rush, 30 minutes - 1 hour will still produce really chewy tasty cookies.

Preheat oven to 350ºF. Line baking sheets with parchment paper

After the cookie dough has had some time to chill, form 2-tablespoon sized dough balls (about 30 g each). Arrange 8 cookie dough balls onto each parchment lined cookie sheet.

Bake the cookies in a fully preheated oven for 10-12 minutes, or until the edges are set and the centers are slightly underbaked. Cool on the pans for 5 minutes before transferring to a wire rack to cool completely.

Melt the remaining chocolate chips in the microwave in 30 second intervals. Dip each cooled cookie halfway into the melted chocolate and then place on a parchment lined baking sheet. Sprinkle crushed candy canes on top of melted chocolate. Allow the chocolate to set and enjoy!