I am so bummed! My cake this weekend melted!!
I did a crusting buttercream and used the upside-down method for frosting. It worked really well!
I then used fondant cut outs and decorated in zebra stripes.
However while working I noticed the frosting starting to sweat and it slowly melted it's way down the cake! My nice neat top edge slid down the sides!! And my friend confirmed it didn't make it very well through the evening. 
I don't know what do have done or why it might have happened but here's a couple thoughts if you guys have input.
1 - I did use this frosting 2 weeks ago and to save it stuck it in the freezer. Is freezing the Crusting Buttercream ok ??
2 - It was raining - not too humid but it was damp outside.
3 - While doing the upside-down method I did put it in and out of the fridge while doing all of the steps.
Any thoughts?
I also live in IL and when icing "melts" it's usually due to the heat or humidity. It shouldn't be a concern this time of year though. One of my other thoughts were...was your cake completely cool prior to icing it? I haven't heard of the "upside down method" so I may not be much help on that, nor have I ever froze icing except for transfers. What Icing Recipe were you using? I use Sharon Zambito's buttercream recipe, ever since then, I have had no issues with my icing at all...no matter what the weather is doing outside.
I used the recipe here called 'faux fondant crusting buttercream II'.
http://cakecentral.com/recipes/1597/crusting-buttercream-faux-fondant-ii/comment-page-1#comment-3874
And yes, my cakes were cool. I had baked them a few days before and froze them.
I just saw someone's post that they had problems with the sweating too.
I guess I'll have to find a different crusting recipe.
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