I spoke to a lovely lady at Thermomix here in the UK about it yesterday. I was annoyed that after leaving the cake filling overnight to cool before I put it between the cakes, it was literally like a rubber ball when I took it out of the dish. I felt that if I threw it at the floor it would bounce back up to me. So I threw it away and rang Thermomix.
It turns out that it is quite a popular recipe with their testers, so it was suggested that I try again, as maybe the scales weren't working properly etc. The lady at Thermomix was trying so hard to help me and even emailed me a recipe for buttercream to use instead. Anyway, when I emailed my thanks, she admitted that the lady tester who had made the recipe recently, cut down the cornflour from 100g to just 70g - quite a big difference. So if I make it again, I have made a note to do just that. Hope this helps anyone thinking of making the cake. I must add that the cake itself is lovely and I have now made buttercream to sandwich it with.
