I'm pretty new to cake decorating, I've only just done my second cake. It was a vegan gluten free carrot cake filled and covered with (vegan) buttercream, which I then covered with marbled sugarpaste and decorated.
It turned out beautifully, but I soon discovered a clear liquid seeping out from the bottom of the cake! Upon cutting the cake, I saw that all the buttercream had melted and had soaked into the cake itself, making it very wet. (Funnily enough I had been worried it would turn out dry as gluten-free cakes tend to be drier than wheat cakes, ironically thanks to the melted buttercream, this cake was actually soaking wet!). It still tasted ok...but a wet cake isn't really desirable and my family were put off trying it. :(. Luckily it was a birthday cake I made for myself (a Buffy one!), but I still wanted my family to be impressed.
I have read in other threads that using margarine is the culprit and will melt under sugarpaste/fondant, which I did not know. I make "buttercream" from icing sugar, a UK brand of margarine called Vitalite (sunflower) and vanilla flavouring. It's delicious and is perfect for filling or topping, but this was the first time I had buttercreamed a cake I was going to cover.
So, my question is, does anyone know of a vegan recipe for buttercream that won't melt under sugarpaste? . Can I simply substitute the margarine with vegetable fat? Or will this also melt or not taste right?