Whisk together flour, cocoa powder, baking soda, and salt in a medium bowl—this ensures even distribution of the leavening agent and salt throughout the dough. In a separate large bowl, beat the softened butter with both sugars for 2-3 minutes until light and fluffy. This creaming process incorporates air into the dough, which helps create a tender cookie texture. While the butter mixture creams, you can have your dry ingredients ready to go.
Add the room-temperature egg and vanilla extract to the creamed butter mixture and beat until fully incorporated. The egg acts as a binder and adds moisture, while the vanilla extract enhances the chocolate flavor. Gently fold in the dry ingredient mixture from Step 1 until just combined—avoid overmixing, which can develop gluten and make the cookies tough. Once the flour mixture is fully incorporated, fold in the milk chocolate chips, distributing them evenly throughout the dough.
Transfer the dough to the refrigerator for at least 2 hours, or preferably overnight. I find that chilled dough is much easier to handle and produces cookies with better shape and texture—the cold dough spreads less during baking and yields a fudgier center. This chilling time also allows the flavors to meld beautifully.
Preheat your oven to 350°F. Remove the chilled dough from the refrigerator and roll it into balls about 1 to 1.5 inches in diameter—consistent sizing ensures even baking. Place the dough balls on a parchment-lined baking sheet, spacing them about 2 inches apart, and bake for 10-12 minutes until the edges are set but the centers still look slightly underdone. The cookies will continue to cook on the hot pan after removal from the oven.
Allow the cookies to cool on the baking sheet for 5 minutes (this helps them firm up), then transfer them to a wire rack to cool completely. While the cookies cool, microwave the peppermint candy kisses in 30-second intervals, stirring between each interval, until they're completely melted and smooth. I recommend using short bursts rather than one long heating time to prevent the candy from seizing or scorching.
Once the cookies have cooled completely, dip the top of each cookie into the melted peppermint candy, then place it on a parchment-lined baking sheet. While the peppermint coating is still wet and slightly sticky, sprinkle each cookie with the crushed candy canes, pressing gently so they adhere. Allow the cookies to set at room temperature for at least 30 minutes until the peppermint coating hardens completely. If you want to speed up the process, you can place them in the refrigerator for 10-15 minutes.