Preheat your oven to 350°F (175°C) and line your baking sheets with parchment paper.

In a large mixing bowl, cream together the softened butter, granulated sugar, and brown sugar until light and fluffy (about 3-5 minutes).

Beat in the eggs one at a time, followed by the vanilla extract. Mix until combined.

In a separate bowl, whisk together the all-purpose flour, cocoa powder, baking soda, and salt.

Gradually add the dry ingredients to the wet ingredients, mixing until everything is well combined but avoid over-mixing.

Gently fold in the chocolate chips.

Using a cookie scoop or tablespoon, drop dough balls onto the prepared baking sheets, ensuring enough space for spreading.

Bake for about 10-12 minutes, or until the edges are set and the centers are still soft and slightly gooey. Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack.

In a medium bowl, combine the marshmallow fluff, powdered sugar, and milk. Mix until smooth and fluffy.

Generously spread the fluffy marshmallow frosting on top of the cooled cookies.

Drizzle melted chocolate over the frosted cookies for an additional touch.