I've made this cake twice. The first time it started to fall apart as I attempted to invert it so I left it on the pan insert. The 2nd time I was able to get it on a plate though there were a couple areas where it collapsed a little. I think the trick is to make sure the jam does not spread to the outter edge; keep it centered over the batter maybe using less of the jam than the recipe suggests. Will try yet again as it is a delicious cake.
I need to amend my comment below. While the cake did fall apart after inverting it, I was able to salvage it by forcing a springform pan around it until it cooled completely. I also think it may have worked if I had let the cake cool completely before inverting it. It tasted great and was a popular dish at my brunch.
Normally I have great luck with recipes from this site, but this cake was a disaster! The hot berries spilled outside of the cake (since they are not mixed into the batter) and made a huge mess. Will not make this again.