Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.

In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy.

Add the eggs one at a time, mixing thoroughly after each addition. Stir in the vanilla extract.

In a separate bowl, whisk together the all-purpose flour, cocoa powder, baking soda, and salt. Gradually mix this into the wet ingredients until just combined.

Fold in the mint chocolate chips until evenly distributed.

Drop tablespoons of the cookie dough onto the baking sheets, spacing them about two inches apart. Bake for 10-12 minutes, or until edges are firm and centers remain soft.