01 - Preheat oven to 350°F and line two baking sheets with parchment paper.
02 - In a large mixing bowl, beat butter, granulated sugar, and brown sugar until light and fluffy.
03 - Beat in eggs one at a time, then incorporate vanilla and peppermint extracts.
04 - In a separate bowl, whisk together flour, cocoa powder, baking soda, and salt.
05 - Gradually add dry ingredients to wet mixture, mixing until just combined. Fold in chocolate chips.
06 - Drop tablespoon-sized dough balls onto prepared baking sheets, spacing 2 inches apart.
07 - Bake for 10-12 minutes until edges are set but centers remain soft.
08 - Let cookies rest on baking sheet for 5 minutes, then transfer to wire rack to cool completely.
09 - Beat softened butter until creamy. Gradually add powdered sugar, milk, peppermint extract, food coloring, and salt, beating until smooth and fluffy. Adjust consistency with additional milk if needed.
10 - Once cookies are completely cool, spread a generous layer of green mint frosting over each cookie.