This rich and creamy Yule log is not for the faint-hearted - it's a decadent triple-chocolate Christmas treat, but it's as easy as making a Swiss roll.
This Christmas roll can be made two ways: with buttercream icing and festive decorations, or filled with cream and berries.
Preheat the oven to 220C/425F/Gas 7. Line a 23x33cm/9x13 in Swiss roll tin with greaseproof paper and brush this lightly with oil.
Combine the caster sugar and egg yolks in a bowl and whisk them together until light and thick. Melt the chocolate with 4tbsp cold water in a bowl over a pan of very gently simmering water. When you can see the chocolate has melted until smooth, stir in the sugar and egg mixture.
Meanwhile, whisk the egg whites until stiff but not dry. Gently fold a spoonful of the egg whites into the chocolate mixture to lighten it, then fold in the remaining whites using a large metal spoon. Do not overmix, and always use a gentle action. Pour the batter gently into the prepared tin and bake for 12-14 minutes (no longer), until risen and just firm to the touch.
Remove to a wire rack and leave to cool in the tin for at least 2 hours.
Once cold, lay a sheet of greaseproof paper on a board. With one bold movement, turn the whole cake onto the sheet of paper, then lift the tin off. Carefully peel away the paper and trim away any scraggy edges of cake.
To make the buttercream icing, beat the butter until soft, then sift in the icing sugar and cocoa. Add the milk and combine together until soft. Spread half the icing over the cake up to the edges.
Roll up as you would a Swiss roll: starting at the long side opposite you, use the paper to roll the cake towards you, around the icing; don't worry about the cracks. Transfer to a flat serving dish. Carefully spread the remaining icing over the cake (you can pipe the icing if you like). Chill until needed, then decorate with festive decorations and sift over some icing sugar.
To make the cream filling, spread the inverted cake with the whipped cream, scatter over the berries and add a few dribbles of Drambuie, if you like. Carefully roll up as described above. Sift over icing sugar just before serving.