Place the semi sweet chocolate in a microwave safe bowl. Heat in 20 second intervals, stir after each interval until the chocolate is fully melted. Set aside for the chocolate to cool.
Cream together the butter, sugar and brown sugar until smooth and fluffy.
Add egg, vanilla and cooled melted chocolate and beat together. You do not want the chocolate to be hot or it will cook the egg.
Whisk together flour, cocoa powder, baking powder and salt in a separate bowl.
Slowly add dry ingredients to the creamed mixture, beating until incorporated.
Roll into 24 1 inch balls. Roll each of these cookie dough balls into a bowl of granulated sugar and place on a cookie sheet several inches apart.
Bake for 10-12 minutes until the edges of the cookies are set. While the cookies are baking, unwrap the Hershey Kisses so they are ready.
Once the cookies are done, place a Hershey Kiss in the center of each cookie once you remove them from the oven.
Then move the cookies from the pan to a wire rack to cool completely.
Notes
The cookies will last in an airtight container for up to 5-7 days.