I tried making SMBC last night and it seemed fine--I kept mixing it until it changed from curdled to nice and smooth. When I tried to fill my cake with it, it was all weird and separated! I popped it in the fridge for 30 mins and when I mixed it--it seemed fine. Every time I try to work with it though it separates. Even if I poke at it with my finger it weeps. Do you guys know why that's happening? I made a big batch and I don't want to throw it away. This is for a cake I am making for tomorrow and so I need to finish it tonight. :-( I have only ever successfully made SMBC once.
I do not own a microwave so I cannot microwave part of the icing and add it to the batch like some people have been suggesting. I've only been mixing it at room temp too, so I don't know what's going on.
Thank you for your help!