In a large bowl, beat the softened butter until light colored. Cream in white and brown sugar. Beat in the vanilla and mint extract and the egg.

In a separate bowl, combine the flour, baking soda, salt and cocoa. Stir into the wet ingredients. Stir in the Andes mint pieces.

Roll the dough into 1 inch balls and refrigerate for at least 2 hours.

Preheat the oven to 350 F. Place the balls on a cookie sheet and bake in a preheated oven for 9-11 minutes. Do not overbake or they will be crunchy.

Remove them from the oven and immediately place 1 and 1/2 Andes mints on the top of the cookie. Let them sit for a minute until the mint has melted and then gently spread on the cookie with a knife. Let them cool completely before storing, Or enjoy them warm.