AHi good evening i am having trouble with hardening marshmallow fondant. Can someone please give me some advice on this please.

Can you give more information? Do you mean with cut out decorations drying or your fondant is hardening too quickly?

If you are wanting mmf decorations to dry, you need to give them a couple days. If it is very humid or hot where you live, that can make the drying take longer. You can put a fan next to them to blow cool air on the decorations to help them dry out a little quicker, but it just takes time!

AHello sixinarow, im having trouble with hardening fondant for bows or any mmf decorations. Ive left it out with an ac full blast overnight and it stays very flexible. ive read about adding gum tex but ive also read not to add it to mmf. : (

You could add some gumpaste to your mmf, but I have added gumtex to it on several occassions. Not sure why you read not to.  I haven't had any issues with it.  I add it to the mmf just like I would regular store bought fondant when I need it to have more elasticity (sp?) and dry quicker.

ACycakes do i add it while kneading or while adding the powdered sugar?

You can add gum paste - if I'm adding it, I make the mmf like usual and just add gum paste into the amount I need to harden - usually a 50/50 mix. It's still going to take at least 12 hours to harden, that's just the nature of mmf. It depends on so many variables (weather, thickness) sometimes it dries in a half a day, other times it takes 5 days! :)

AOh wow! Thank you so much for the info im going to try it tomorrow see how it turns out!! Thanks a bunch for the 411