Prepare the Dough:

1. Cream butter and sugars:
   • In a large mixing bowl, beat the butter, granulated sugar, and brown sugar together until light and fluffy, about 2-3 minutes.
2. Add wet ingredients:
   • Mix in the egg and vanilla extract until fully combined.
3. Combine dry ingredients:
   • In a separate bowl, whisk together the flour, cocoa powder, baking soda, and salt.
4. Form the dough:
   • Gradually add the dry ingredients to the wet mixture, mixing until just combined. Cover the dough and chill in the refrigerator for at least 30 minutes.

Shape the Cookies:

5. Preheat the oven:
   • Preheat your oven to 375°F (190°C) and line baking sheets with parchment paper.
6. Form and roll:
   • Scoop out tablespoon-sized portions of dough and roll them into balls. Roll each ball in the granulated sugar until coated.
7. Place on the baking sheet:
   • Arrange the dough balls about 2 inches apart on the prepared baking sheets.

Bake and Add the Chocolate:

8. Bake:
   • Bake for 8-10 minutes, or until the cookies are set but still soft in the center.
9. Press the chocolate kiss:
   • Immediately press a chocolate kiss into the center of each cookie while they are still warm. The cookie will crack slightly around the edges—this is normal.
10. Cool:
    • Allow the cookies to cool on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely.