My first "outside" wedding cake next weekend. Will buttercream under fondant melt down if heat is over 80? What about cream cheese filling under fondant? Does adding marshmallow to cream cheese help it hold up in the head? Worried after reading forums on melting buttercream, but wasn't sure if that meant under fondant too? Should I change my buttercream to all shortening? Thanks

I would use an all-shortening buttercream. Indydebi's is great!

Buttercream will melt under fondant like it will regularly. The difference is that when it melts under fondant, you get a bulge or wrinkles in the fondant.

also sugarshack has a wonderful recipe. you can see her making it on youtube. she uses hi-ratio shortening. that stands up to heat better than reg. shortening. it makes your icing taste and feel a lot better than using reg. shortening.hth