In a large bowl, combine the cake mix, eggs, vegetable oil, and peppermint extract. Stir until everything comes together into a soft dough.
Refrigerate the dough for 20–30 minutes. It helps keep the cookies from spreading too much.
Set your oven to 350°F and line a baking sheet with parchment paper.
Scoop the chilled dough into 2-tablespoon portions (about 1.5 oz) and roll into balls. Place them 2 inches apart on the sheet.
Bake for 9–11 minutes, just until the edges are set but the centers are still soft.
Let cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.
While the cookies cool crush the peppermint into small pieces. Chop the chocolate chips up roughly and add to a microwave-safe bowl.
Once the cookies are cool place the bowl of chopped chocolate in the microwave and cook for 30 seconds before stirring and then continuing to cook for 15 seconds at a time until melted and smooth.
Dip each cookie into the melted chocolate so that it coats one half. Sprinkle crushed peppermint over the chocolate and set cookies aside to allow the chocolate to harden.
Once the chocolate has hardened enjoy!