Preheat oven to 350 degrees F and prepare two baking sheets with parchment paper
In a medium bowl combine the flour, cocoa powder, baking soda and salt; set aside
In a mixing bowl with paddle attachment cream together the butter and brown sugar until smooth
Add in the egg and vanilla extract and continue mixing until fully combined, scraping down the sides between mixing
Gradually add the dry ingredients to the butter mixture and mix until combined and dough comes together
Scoop the dough into ¾ ounce balls (1 tablespoon), roll them in granulated sugar or sugar crystals and place on a baking sheet about 2 inches apart
Bake the cookies for 7-8 minutes, remove the tray from the oven and gently press the chocolate kisses on the top of each cookie
Allow the cookie to cool and the chocolate will harden again
Store in an airtight container until ready to serve!