Preheat the oven to 350°F (175°C).
In a large mixing bowl, cream together the softened butter and sugar until light and fluffy.
Beat in the eggs one at a time, then stir in the vanilla extract.
In another bowl, whisk together the flour, cocoa powder, salt, baking soda, and baking powder.
Gradually add the dry mixture to the wet mixture, stirring until well combined.
Fold in the Andes mint pieces.
Using a tablespoon, drop dough portions onto a baking sheet lined with parchment paper.
Bake for 10-12 minutes or until the edges are set.
Allow cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.