Preheat oven to 350°F (177°C). With an electric or stand mixer fitted with a paddle attachment, cream together the butter and sugars on medium speed. Add the egg, then the egg yolk, mixing for about 1 minute after each addition. Mix in the vanilla extract.

In a separate bowl, whisk together the baking soda, baking powder, salt, flour, and unsweetened cocoa powder. Add 1/2 of the dry ingredients to the wet. Mix for about 1 minute on low speed. Add the rest of the dry ingredients and mix on low speed until combined. By hand, fold in the Andes Mints.

Drop by rounded tablespoon-fuls* onto ungreased baking sheet or silicone mat. Bake for 10-12 minutes until sides *slightly* begin to brown. I took mine out of the oven at exactly 10 minutes. Allow to cool on the baking sheet for 2-3 minutes and transfer to a wire rack.