Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a large mixing bowl, beat the softened butter and brown sugar until light and fluffy.
Add the egg and vanilla extract and mix until well combined.
In a separate bowl, combine the all-purpose flour, cocoa powder, baking soda, and salt.
Gradually add the dry ingredients to the wet mixture, stirring gently until a dough forms.
Fold in the chopped cherries and semi-sweet chocolate chips, distributing them evenly throughout the dough.
Using a cookie scoop or spoon, drop portions of dough onto the prepared baking sheet, leaving space between each cookie.
Top with additional chopped cherries and chocolate chips, if desired.
Bake for 13–15 minutes, until the edges are slightly crisp.
Remove from the oven and allow the cookies to rest on the baking sheet for 2–3 minutes.
Transfer the cookies to a wire rack and allow them to cool completely.