Cream together the softened butter, brown sugar, and granulated sugar until light and fluffy, about 3-4 minutes.

Beat in the egg and mint extract until well combined.

Sift in the all-purpose flour, cornstarch, salt, and baking soda. Mix on low speed until just combined.

Fold in the Andes creme de menthe baking chips and refrigerate the dough for at least 60 minutes.

Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

Use a cookie scoop to form 2-tablespoon-sized balls and roll them in the remaining mint chips.

Bake the cookies for about 12 minutes or until the edges are lightly browned.

Prepare the Andes Mints by cutting them into triangles while the cookies are baking.

Immediately press the cut triangles of Andes Mints into the center of each warm cookie, and allow to cool on the baking sheet.