Preheat your oven to 325 degrees Fahrenheit.
In a large mixing bowl or in the bowl of a stand mixer, cream together ½ cup unsalted butter, ½ cup packed light brown sugar, and ¼ cup granulated sugar until light and creamy.
Add 1 large egg and 2 teaspoons vanilla extract into the cookie dough and beat again until just combined.
Add 1¼ cups all-purpose flour, ¼ cup unsweetened cocoa powder, ½ teaspoon baking soda, and ¼ teaspoon salt and beat until just combined. Do not overmix.
Use a wooden spoon or rubber spatula to mix in ½ cup semisweet chocolate chips and ¾ cup chopped Andes mints until evenly distributed.
Scoop the cookie dough onto an ungreased cookie sheet using a #24 cookie scoop (about 2 ½ tablespoons each).
Bake in the preheated oven for 12–15 minutes or until the edges set but the centers are still soft. As soon as you remove the cookies from the oven, press more Andes mints onto the top of the cookies.
Allow the cookies to cool on the baking sheet for a few minutes. After 5 minutes, transfer the cookies to a wire rack to cool the rest of the way.
Serve and enjoy!