How long does is take to freeze a marshmallow?

Answer 1

It will take a matter of seconds if you dip it in liquid nitrogen. Predicting the time would require knowing the ambient temperature and the size of the marshmallow.

Since the moisture in the marshmallow is mostly dissolved in sugar to make a very concentrated syrup that is stiffened with starch so it will hold air, I would venture to say that the moisture would not freeze in an ordinary kitchen freezer because the temperature is not low enough to hit the depressed freezing point...put some pancake syrup in an ice cube tray and see if you can get it to freeze...the marshmallow is even more concentrated.