My first thought is dowels – hope you used them.
Secondly, you froze the cake and thawed them “a bit”. Maybe there was too much ice in the cake with not totally thawing and it melted after the fondant was put on and therefore, the cakes shrunk where the ice had been. A possibility.
In future, I would suggest you freeze the cakes, thaw them in the fridge overnight and then cover them with the buttercream and then apply the fondant. You can chill the buttercream cakes but do not freeze them. Might be better results.
June Lynch, Dundas, Ontario, Canada
