Preheat your oven to 180°C (350°F) and prepare two baking sheets by lining them with parchment paper.

In a medium bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking soda, and salt until combined.

In a large mixing bowl, use an electric mixer to cream the softened unsalted butter with both sugars until light and fluffy, about 2-3 minutes.

Beat in the eggs one at a time, mixing well, then add the vanilla extract until everything is combined and smooth.

Gradually add the dry ingredients to the wet mixture, mixing slowly to avoid overworking the dough.

Carefully fold the mini marshmallows into the cookie dough using a spatula.

Drop rounded portions of dough onto the prepared baking sheets, leaving space between each scoop.

For decoration, press a few additional mini marshmallows onto the tops of the cookie dough scoops.

Bake for 10-12 minutes until the edges are set and centers are slightly soft.

Allow the cookies to cool on the baking sheets for about 5 minutes before transferring to a wire rack to cool completely.