Can you use all purpose flour instead of icing suger for marshmallow fondant?

You can't directly substitute all-purpose flour for icing sugar in marshmallow fondant. Here's why:

* Texture: Icing sugar is fine and powdery, crucial for creating the smooth, pliable texture of fondant. All-purpose flour is coarser and will result in a grainy, lumpy fondant.

* Sweetness: Icing sugar is very sweet, contributing to the desired flavor profile of fondant. All-purpose flour is not sweet at all, leaving your fondant bland.

* Structure: Icing sugar helps bind the marshmallow together, creating a firm yet workable fondant. Flour will not provide this structure, resulting in a sticky, runny mess.

Alternatives:

* Powdered sugar: You can use powdered sugar, which is the same thing as icing sugar.

* Confectioners' sugar: Another term for icing sugar.

* If you're out of icing sugar: You could try adding a small amount of cornstarch to the marshmallow mixture to help with texture, but it will not be as smooth or as reliably workable.

Important Tip: Always use high-quality, fresh marshmallows for the best results.