Combine the butter and brown sugar in a mixing bowl and beat together until light and fluffy.
Add the eggs and the vanilla, mix until just combined.
Slowly stir in the flour, cocoa powder, baking soda and salt. Once incorporated – beat well for about 60 seconds.
Cover and refrigerate for at least 1 hour.
Once the dough has chilled – preheat the oven to 350 degrees.
Line a baking sheet with parchment paper.
Place the granulated sugar in a small bowl.
Scoop the dough and roll into a ball.
Roll the dough in the granulated sugar and then place on the prepared baking sheet. Space the cookies about 2” apart.
Bake for 10-11 minutes.
If adding the cinnamon candies to the center - press them into the center of each cookie immediately after removing the cookies from the oven. Then allow them to cool.
Allow the cookies to cool on the baking sheet for 7-10 minutes before transferring to a wire rack to cool completely.