We are making a cake for a silent auction...it'll be sitting out for a few hours. What type of icing/frosting is okay for that long without having to be refrigerated? The event is indoors, but with people coming in and out in 95 degree temps, it could be around 78-82 degrees inside.

Last week on a cake, we used Bronwen's buttercream recipe, and it was great, but it's made with buttermilk so I'm not sure if that's okay to use on this or not. Thanks for any help here!!

I've done several cakes for auctions and I found that the crusting buttercream recipe from this site works like a charm! And a cake with no filling should do rather well without refrigeration.