In a medium bowl, whisk together the all-purpose flour, Dutch cocoa powder, baking soda, and fine sea salt until evenly mixed. Set aside.

In a large bowl or stand mixer fitted with the paddle attachment, cream together the softened butter, dark brown sugar, and granulated sugar on medium-high speed for 2 to 3 minutes until pale and fluffy.

Add the egg, vanilla extract, and pure peppermint extract. Beat on medium speed for 1 minute until smooth and velvety.

Turn the mixer to low speed and gradually add the dry flour mixture, mixing just until no flour streaks remain. Gently fold in the dark chocolate chunks with a silicone spatula.

Cover the bowl with plastic wrap and chill the dough in the refrigerator for 30 minutes to make scooping easy and prevent over-spreading.

Preheat oven to 350°F (175°C) and line two large baking sheets with parchment paper. Scoop 1.5-tablespoon balls of chilled dough and place 2 inches apart on the baking sheets.

Bake for 9 to 11 minutes until the edges are set and tops are crinkled, but the centers still look soft and slightly gooey. Cool on the baking sheet for 5 minutes, then transfer to a wire cooling rack.

Melt the white chocolate in a microwave-safe bowl in 20-second increments at 50% power, stirring between each burst until smooth and pourable.

Drizzle the melted white chocolate generously across the cooled cookies with a fork or piping bag, then immediately shower with crushed peppermint candy cane pieces before the chocolate sets!