Edna I have never used Satin Ice. Forgive my ignorance, is that used the same way as fondant?

I have never had this happen before and I've done nothing but mmf for the last yr. Even in the cruddiest weather and no problems.

But I'd like to hear more about Satin Ice.

does this happen with regular fondant or MMF?

I completely agree with some of the other posts that it is the amount of moisture in your cake that was the problem. Box mixes do tend to be more moist, and then if you are adding extra oil, etc and then covering it with fondant, I can totally see why it got gummy. I am a scratch baker, and we all know that scratch cakes tend to be a little more on the dry side than box mixes...I pretty much only work with fondant, and have never had a problem with my cakes being gummy. I will say, though, that I HAVE noticed that on my cakes covered in fondant, they are more moist than when just covered in buttercream. If I were you, I would play with your recipe...make a few small cakes from different recipe variations, and cover them with fondant. Let them sit for a few days or more, and then cut into them. When you find one that works, make a larger cake and do the same thing. It's kind of a waste of cake, but then you will have peace of mind!

BTW, Satin Ice is a brand of fondant that is commonly used. You use it exactly like you would MMF. It's more expensive, but personally I feel that the quality is so much better...and I can't stand making mmf! IMHO!

So much wonderful information. Thank you for sharing. I will most definately adjust my recipe! I will also be on the lookout for Satin Ice. I've not seen that around but will delve deeper in my search.
Thank you very much.
It's so nice to have other bakers who actually know and are willing to share that knowledge.

I purchase it from Global Sugar Art. I only have AC Moore and Michaels around me, and that is definitely not something they carry! If you have specialty cake stores near you, they might have it.

Sorry I didnt respond before, I was in a brand of fondant. It is not the best one out there, but for the price it works well..
Edna