Do you struggle with your marshmallow fondant being too soft? Do your designs not hold their shape? If so, you will want to know how to harden marshmallow fondant.
Add 3/4 of the powdered sugar to the melted marshmallows in a large bowl. Carefully fold the powdered sugar into the marshmallows using a wooden spoon.
Generously grease a clean working space in your kitchen with shortening. Cover your hands in shortening and turn the marshmallow fondant onto your work surface.