In a large mixing bowl, use a hand mixer or stand mixer to thoroughly mix the sugar cookie dough and the cocoa powder.
Cover dough with plastic wrap and chill in the refrigerator for about one hour.
Preheat oven to 350°F.
Use a cookie scoop to form even balls of dough. Roll the balls in the palm of your hands to form a smooth cookie.
Roll each cookie dough ball in a shallow bowl filled with the coarse sugar until completely coated.
Place the balls 1½ inches apart on a cookie sheet lined with parchment paper. Flatten the top of the cookies just a bit with the palm of your hand to help them spread evenly.
Bake for 8 to 9 minutes or until the cookies are puffy and the dough no longer looks wet.
Remove cookie sheet from the oven. Press a chocolate kiss gently into the top of each warm cookie and allow cookies to cool for a couple minutes before carefully transferring to a cooling rack to cool the rest of the way.
PRO TIP:You could roll the cookie dough in colored sanding sugar or use another variety of Hershey’s kisses for decoration/flavor.PRO TIP:Don’t skip the chilling step as it will help avoid ending up with flat cookies.PRO TIP:Make sure to add the kiss while the cookies are still warm. You want them to stick to the top of the cookie and they won’t do that if the cookies are already cooled.