In a separate bowl, combine flour, baking soda, and salt.
Add the dry ingredients to the butter mixture.
Beat in cocoa powder.
Chill for an hour.
Preheat oven to 350 degrees.
Roll into balls and roll into sugar. Place onto a prepared baking sheet a couple inches apart.
Bake for 8-10 minutes. Allow them to cool on the pan for 5 minutes and then transfer to cooling rack.
Once the cookies are cooled, melt chocolate chips and peppermint extract. Dip one side of each cookie into the mixture and sprinkle with Andes peppermint chips. Let chocolate harden (place in the refrigerator to speed up the process.)