Welcome to the Cake Decorators Q&A

hi with the very hot weather my buttercream is not stiffening up I do 500g real butter then 1000g icing sugar and vanilla paste in never had a problem until the summer I’ve tried trex and butter but that never worked either I also tried adding white chocolate but when crumb coating it just will not hold up leaves the cake bulging when fondent covered
would it be ok to fill with buttercream and then do a white choc ganache for crumb coating would that survive no bulges or any other recipes that would work
thank you xx

Hello annabel

The cake can be filled with butter cream and crumb coated with white ganache. White ganache takes longer to set so in this hot weather add a little more chocolate to cream.
Here is the ganache chart http://www.cakeflix.com/blog/how-to-ganache-cakes-without-gnashing-your-teeth
Make the ganache up according to the chart but if your ganache doesn’t set add more melted chocolate to the made up ganache. Pop the cake in the fridge for a short while to set the chocolate.
If you would still like to use butter cream for the crumb coat try using more icing sugar to butter than you have been. Crumb coat as normal and put the cake in the fridge for the butter cream to set.