In a stand mixer fitted with the paddle attachment or with a hand-held mixer, beat the butter on medium speed until smooth, about 1 minute. Add the granulated sugar and brown sugar and beat on high speed for 1-2 minutes or until light and fluffy. Then, add the egg and vanilla extract and beat until smooth.
Dry ingredients: In another bowl, whisk the flour, cocoa powder, baking soda, espresso powder, and salt.
Add the dry ingredients to the butter mixture. On low speed, beat until smooth and evenly combined. Fold in the chocolate chips until evenly combined. This is a thick batter.
Cover the dough with plastic wrap (make sure the plastic wrap is touching the dough), and refrigerate at least 3 hours or overnight.
When ready to bake, preheat oven to 350 degrees F. Let the dough sit on the counter for about 20 minutes to make it easier to scoop. Line 2 large baking sheets with parchment paper. Scoop about 1.5 tablespoons of dough and roll into a ball, line it up on the prepared baking sheet. Repeat with the remaining dough.
Bake 8-10 minutes on the middle rack of the oven. Don’t worry if they look soft and jiggly, they will harden while they cool down. Once they have cooled down a bit, transfer them to a cooling rack. Let cool completely.
Once cooled completely, place the white chocolate in a microwave-safe bowl and melt them in the microwave oven, checking every 10-15 seconds and stirring each time. Dip each cookie halfway through the melted chocolate, or drizzle over the cookies, and place them on a baking sheet lined with parchment paper. Top with crushed peppermint candy. Let them cool at room temperature or in the fridge until the white chocolate has hardened. Enjoy!