Prepare Baking Sheets and Preheat Oven: Line two baking sheets with parchment paper and preheat your oven to 350°F (175°C).

Mix Dry Ingredients: In a medium bowl, whisk together all-purpose flour, unsweetened cocoa powder, baking soda, and salt.

Cream Butter and Sugars: Cream the softened unsalted butter with granulated sugar and brown sugar for 2-3 minutes until light and fluffy.

Combine Wet Ingredients: Add the large egg, vanilla extract, and milk to the creamed mixture and mix until just combined.

Incorporate Dry Ingredients: Gradually add dry mixture to wet ingredients until a smooth dough forms, folding in mini chocolate chips if using.

Shape Cookies: Scoop out 1-inch balls of dough and place them on the prepared baking sheets, leaving space between each ball.

Bake: Bake in the preheated oven for 8-10 minutes until edges are set and centers are soft.

Add Toppings: Press a peppermint-striped chocolate kiss into the center of each warm cookie and sprinkle with crushed peppermint.

Cool: Allow cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack.