Preventing heavy top layer of cake from crushing cream layer I'm making a flourless cake with almond meal, thus quite dense, and it's also covered completely with whole cherries. 

I thought I'd slice the cake horizontally and put a layer of cream in. The top layer will be quite heavy and I fear the cream will be squeezed out the sides. I wouldn't mind this too much normally, however I'll be transporting it in the springform tin I baked it in and suspect the squeezed out cream will smudge everywhere. 

Just beat the cream until it's stiffer? Is there some additive that makes the cream firmer? The cream I was just planning on whipping it with confectioner's (icing) sugar and vanilla extract.

Update:

Gelatine method below worked perfectly with Australian Thickened Cream(35%, pre-thickened with Carrageenan and guar gum--I thought Aussie stuff was pre-thickened with gelatine?). Cream came out thick and did not squeeze out the sides when the heavy top layer was put on.
To make the whipped cream firmer, you could set it with gelatine or agar (which I think would be better unless the cake is being refrigerated until just before serving). For the recipe, I refer you to http://video.about.com/southernfood/How-to-Stabilize-Whipped-Cream.htm (video).
Having looked at the video, you might even want to add a half more of the gelatine/agar so it is really set (much like a pastry cream in a fraisier).
Also, if a creamy filling is required could a pastry cream be used instead of whipped cream? It would set and cut much better (although would lose the lightness of whipped cream which you may be after - you could fold whipped egg whites or cream into it but then you have the same problem of it squeezing out).