I am making a cake for a cowroker's baby shower. The shower was suppsed to be 2 weeks ago but his wife went into labor the day before the shower however i had already made the buttercream frosting for the cake. The frosting has been in the fridge in a ziploc tupperware since then. I used the wilton recipe with shortening and merginue powder. Is the frosting still good or do I have to make more?
I'd make more just to be on the safe side. I've never personally tasted "old" icing. Good luck! 
I'd make more just to be on the safe side. I've never personally tasted "old" icing. Good luck!
Wilton advises that both their purchased and homemade buttercream can be safely stored for two weeks. 
Here's a link to the Wilton frosting storage info:
http://www.home-ec101.com/how-sweet-it-is-a-frosting-dilemma/
HTH
In Course 1 Wilton actual says the icing can be kept on your kitchen counter for 2 weeks. I have kept it in the fridge for longer with out any problem at all.
It will be fine. Just mix it up a little before using.
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