Stir in the brown sugar, granulated sugar, vanilla, egg, and egg yolk.
Add in the flour, dark cocoa powder, and baking powder. Stir until combined.
Stir in the chocolate chips until they are evenly distributed.
Cover and chill the cookie dough for at least 1 hour.
Crush the candies in a zip bag on a cutting board using a mallet or a rolling pin.
Preheat the oven to 350°F. Line a sheet pan with parchment paper.
While the oven is preheating, roll a generous tablespoon of dough into a ball and dip the top of the ball into the crushed candies, pressing to adhere.
Space the cookies apart by 2 inches on the pan.
Bake the cookies for about 9-11 minutes, until the center starts to look matte and the edges are firm. Remove the pan from the oven and let the cookies rest on the pan for 2 additional minutes.
Transfer the cookies to a cooling rack. Seal in an airtight container.
Nutrition facts are sometimes provided below and are calculated using an online calculator. With specific brands of ingredients and additions, omissions, or substitutions the nutrition facts may change. We encourage you to use your own nutrition facts calculator to obtain the most accurate nutrition facts for your meal.