Melt the white chocolate in the microwave and smooth it out on a layer of baking paper. Press another piece of baking paper on top and roll the whole thing up. Set in the fridge for at least two hours, then, in one movement, unroll the bundle - you should be left with chocolate shards. If not, break them up with your hands.
Preheat the oven to 200°C.
Use an electric mixer to whisk together eggs and caster sugar until fluffy, smooth and light. Sift in self raising flour and cocoa powder and fold gently in the mix, being careful not to get rid of any of the air.
Pour into a lined 23 by 33 cm tin and spread to the corners. Bake for around 10 minutes then immediately turn out onto a large sheet of baking paper. Use a knife to cut 2.5cm in along one of the long sides, then roll the whole thing up tightly (keeping the paper inside the roll). Set aside to cool completely resting on something so it doesn’t unravel.
Meanwhile, whisk softened butter and melted white chocolate together. Add baileys, a spoonful at a time, then icing sugar until the mixture becomes stiff looking.
Unroll the cool cake and spread it with the chocolate buttercream. Sprinkle with chopped raspberries and roll up again.
At an angle cut around 6cm of the log off and position it against the side of the larger log - it should start looking treelike at this point!
Use a spatula to spread the remaining buttercream along the outside of the log, making sure you cover the whole thing. Press the chocolate shards into it to create a bark effect.