Ooh Shereen, I've also got a can of chestnut puree lurking in the cupboard - bought it ages ago when it was some ridiculously cheap price but then didn't know what to do with it .  I do recall seeing a recipe somewhere for chestnut and mushroom soup, using chestnut puree, but can't remember the details.

I'd also be interested in any other ideas, thanks for bringing it up.

 Shereen,

Here is an interesting recipe using chestnut puree & almonds & iced with chocolate ganache.  If you wanted the cake itself to be chocolate flavoured I am sure you could add some cocoa powder or chips of chocolate. Personally I would love the contrast of the mousse-like nut cake with the sumptuous chocolate ganache on top.  The original recipe is in Portuguese at the end which you can use the translator on. 

http://www.azeliaskitchen.net/blog/chestnut-almond.....airy-free/

As you can see this is a gluten & dairy-free cake so I will also post it on the appropriate thread so it will be easy to find for people who need who suffer from these allergies. 

I too have a lurking tin of chestnut puree in my cupboard¦..!!