i made something last night which was super easy and really yummy.
It was a chocolate mousse type thing - mix mascarpone cheese with melted chocolate, put in little ramekins and stick in the fridge to set. so easy and totally delicious. as its for a dinner party you could stick a strawberry on top and dust with icing sugar or something. Ta dah!
Or Pannacotta - has to be one of the easiest around - is basically just set milk/cream with flavourings (which you can vary - no need eg for the limoncello liqueur!) It is delicious and can be made in advance and a bit trendy too among foodie progs.
I usually use vanilla in the Pannacotta and then blitz and sieve some frozen raspberries with a touch of icing sugar for a 'coulis' to sit the panna in and it looks stunning and is very simple.
well i didnt measure - i just dumped a load of oddments of choccy in the microwave - half a bar of green and blacks, one whispa, three squares of lindt. I added a whole pack of mascapone - maybe 250g? To be honest i dont think it matters much. Just make sure you make more than you need because you WILL eat half the mixture while you are making it
My mum does an amazingly sophisticated one with whole rish tea biscuits dipped in strong coffee layered with chocolate ganache and almonds and topped with a layer of melted dark chocolate and whole blanched almonds.