I used my mum's method of making a plain roll and using Nutella for the filling. Then I smothered it with a centimetre of buttercream, because I really like buttercream (though I may now have discovered my limit).
The wonderful thing about Yule log is that the more unholy a mess you make of the icing, the more it looks like a piece of wood.
I've brought most of it into work today to save me from myself. Both end pieces, however, are mine.