I've tried making marshmallow fondant on several occassions. It turns out fine and works great.....UNTIL.....the finsihed cake is set out for display at the event.....within about 30 minutes, the fondant has drawn so much moisture that it's turning into goo. This has happened at several different venues and different times of the year........

Anyone else had this issue? Anything that could be added [i.e. tylose] to help make it more stable?

I make MMF but I add white chocolate chips and white karo syrup to mine. I have had excellent results. The ratio is 1/2 C of white choc. chips and Karo to 2 one lbs. bags of mini marshmallows. You may be warming the cake up too fast, such as taking from the cooler to a room that is too warm. Not sure what else could be causing the problem. Good luck.

That sounds so yummy to add white choc and karo, is it a 1/2 cup of each that you add?

Yes, a half cup each of karo and white choc. I have had great results using this.

Do you have a lot of humidity where you live? Maybe that's it. I live in a dry climate and I've never had that happen

I use the basic MMF recipe (marshmallows, conf. sugar, and water) all the time and never have that happen - wait, should I knock on wood? My cakes are kept at room temp. Do you put yours in the fridge? When the cake comes to room temp it could produce extra moisture that might cause the Fondant to turn soft.

Has anyone used tylose powder to make it more pliable? I will try the karo and white choc trick, plus it sounds really tasty!