Preheat your oven to 350°F, then line a baking sheet with parchment paper.
Unwrap your chocolate kisses and place them in the freezer to chill.
In a large bowl, mix the butter (softened) and brown sugar. Then, add the egg and vanilla and mix until creamy.
In a separate bowl, whisk the flour, cocoa powder, baking soda, and salt. Add to the wet ingredients, stirring until just combined.
Chill your dough for 20-30 minutes or until it's easier to scoop out and roll into a ball.
Roll into 1-inch balls, then dip into the granulated sugar to coat.
Bake for 10-12 minutes or until the edges look set and slightly cracked.
After removing them from the oven, gently press the chocolate kiss in the middle of the cookie.
Let the cookies cool on the baking sheet until the Hershey kisses are set, and enjoy!