Line an 8×8-inch baking dish with parchment paper, leaving a little extra on the sides for easy lifting.

In a medium saucepan over low heat, melt white chocolate chips with sweetened condensed milk, stirring constantly until smooth and creamy.

Remove from heat and mix in vanilla extract until glossy and fragrant.

Pour the mixture into the prepared pan, smooth the surface, and press mini marshmallows on top to form ghost shapes.

Let the fudge sit for about 10 minutes, then add candy eyeballs or mini chocolate chips for eyes and draw mouths with black gel icing.

Refrigerate for 2 hours or until firm. Lift from the pan, slice into squares, and serve chilled.