Begin by preheating your oven to 350°F (175°C). Line a baking sheet with parchment paper for easy cleanup.
In a mixing bowl, whisk together the flour, cocoa powder, baking soda, and salt until well combined. Set this mixture aside.
In another bowl, beat the softened butter with the granulated and brown sugars until the mixture becomes light and fluffy. This usually takes about 2-3 minutes.
Add the eggs one at a time, mixing well after each addition, then stir in the vanilla extract.
Gradually add the flour mixture to the wet ingredients, stirring until just combined. Avoid overmixing!
Gently fold in the chopped Andes mints until evenly distributed throughout the dough.
Scoop rounded tablespoons of dough onto your prepared baking sheet, leaving enough space in between each cookie.
Bake in the preheated oven for about 10 minutes, or until the edges are set. The centers will look slightly underdone; that’s perfect!
Allow the cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.
Notes
These cookies store wonderfully in an airtight container, and their flavor actually improves after a day!