Preheat your oven to 350°F (175°C) and line a 9x13-inch baking pan with parchment paper for easy removal.
In a large mixing bowl, whisk together melted butter and sugar until smooth and slightly shiny.
Add the beaten eggs and vanilla extract to the wet mixture, whisking until fully combined and silky.
Sift together the cocoa powder, flour, and salt in a separate bowl to aerate and remove lumps.
Gradually fold the dry ingredients into the wet mixture using a spatula, just until no streaks remain.
Stir in the chocolate chips, ensuring they are evenly distributed throughout the batter.
Pour the batter into the prepared pan, spreading it evenly with a spatula to smooth the top.
Bake in the preheated oven for about 35 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs.
Once baked, let the brownies cool completely in the pan on a wire rack for about 15-20 minutes.
Meanwhile, cut the marshmallows in half diagonally to create ghost shapes; set aside.
Arrange the marshmallow ghosts on top of the cooled brownies, pressing gently to adhere.
Optionally, use chocolate or icing to add small eyes to the marshmallow ghosts for extra detail.
Slice into squares and serve these spooky, chocolaty treats, perfect for Halloween parties or haunted movie nights!
