Good morning!  So I am still kind of new to this, I have made 2 cakes in the last few months using home made MMF and it worked great, one of them was a three tired 10", no issues.  I attempted to make a 3 tiered 10" yesterday and it was a giant fail.  I had made some fondant 2 days ahead and wrapped it tightly in plastic wrap, I tried to put it on the cake and it just wripped.  So I thought maybe it was the cheap marshmallows, so I went and got jet puffed marshmallows and domino sugar, still had the same issue.  I took to the internet again, it seamed dry, so I added water, nope, still ripped.  I added shortening, I added glicerin, I added more marshmallow, I added more powdered sugar.  I made about 6 batches, adding different things, same problems.  It just seamed to be too soft and had no elasticity.  When I added the powdered sugar, it seams to stiffen it up, but it still tore away because of the lack of elasticity.  I ended up buying Wilton fondant just to get it done, which I really hate the taste of, but oh well.  Even with that one, I had to make it a bit thicker than 1/8 inch to prevent ripping.  Is there something wrong with my kitchen?  I am so lost as to what I did wrong, I tried every trick I could find.  Thank you for your help!

i’ve made marshmallow and regular fondant but I primarily bought it to avoid the hassle and economize my time —

so as far as trouble shooting — did you knead whatever fondant about fifty times before rolling it out? you can even microzap it for a few seconds at a time if it’s a large blob and again to economize time and energy — but literally seconds — for a large piece, maybe four or five seconds to start — then check it, squish it around, then 2-3 seconds, continue as needed— every bit needs to be fully worked before you start rolling — like fifty nice smooth kneads —

but I mean right before you roll it out — not just in sometime in advance — it needs to be awakened — warmed up with the kneading but not at all melted in the microzapper — aka microwave —