Preheat oven to 350°. Line two baking sheets with parchment paper, set aside.
In a medium sized bowl, toss the flour, cocoa and baking soda together, set aside.
Cream the butter and sugars together until smooth. Add in egg and vanilla and mix until smooth. Pour in flour mixture and mix until just combined. Fold in oreos an Andes mints by hand with a rubber spatula until evenly distributed. This is optional, but I reserved 1/4 cup of each to press into the top of my cookies for a visual pop.
Scoop dough into 2 rounded tablespoons each and place on baking sheet. Press some oreo and mint pieces into the top. Repeat this process until all dough is rolled and onto baking sheets. Bake cookies for 8-10 minutes or until edges are set. Center of cookies will be underdone but that is what makes them chewy. Let cookies cool on baking sheet for 5 minutes before transferring to a wire rack to finish cooling.
Cookies will stay soft for up to 5 days in an airtight container.