I have a wedding cake to do the day after tomorrow. When booking, I told the bride that if she was going to put the cake outside, I would suggest a fondant instead of buttercream frosting because buttercream will not hold up in the heat very well. She still wanted the chocolate buttercream & wasn't positive on where she was going to put the cake. It has been getting pretty hot outside & I called her today to find out where she has decided to have the cake set up & she said she is definitely going to put her buttercream cake outside but it will be under a tent in the shade. I told her that since it was still risky, I would upgrade her to a fondant frosting at no extra charge if she has changed her mind. She said "No...... if it starts melting, we'll just hurry up & eat it". Being that I've already warned her about the buttercream possibly melting in the heat & she knows it's not a great idea, but still wants to do it, does anyone have any tricks to make it more stable, etc? Possibly adding more meringue powder or something?

I haven't tried this, but Indydebi says it holds up in the heat:

http://www.cakecentral.com/cake_recipe-6992-24-Indydebis-Crisco-Based-Buttercream-Icing.html

Another popular recipe is the high humidity b/c:

http://www.cakecentral.com/cake_recipe-4123-High-Humidity-Buttercream.html

HTH

Its nice you are trying to be so accommodating to this bride who is being very naive!! Do what you can but she's going to see the mistake when her cake is melting all over !

I don't know if you have already done this cake (the dates look a little bit messed up in the forum posts?) but you should probably have her sign something when you deliver the cake stating that you are not responsible for any problems if the icing does melt and that she was informed of this possibility and declined to make changes to her cake (if you don't already include this as part of your contract). Just to cover yourself!