To make the ganache, put the white chocolate and double cream into a microwave safe bowl
Microwave on high for 30 seconds, then stir well. Keep microwaving in 10 second blasts, stirring between each one, until the chocolate is fully melted. Set aside to cool and thicken. If you don't have a microwave, do this in a pan on a low heat
Pre-heat your oven to 160C Fan/350F/Gas Mark 4, line a swiss roll tin or a baking tray with a lip, with baking paper. I used a Salter tray measuring 38.5 cm x 25.5 cm x 2.2 cm
For the sponge, whisk the eggs and sugar together with an electric whisk or in a stand mixer for around 8 minutes until it reaches 'ribbon stage' - this is when you can drizzle the mixture in a figure 8 and it takes at least 3 seconds to sink back in. It will also be very light in colour and have doubled in size
Add the vanilla and mix it in briefly
Gently fold in the flour, ideally using a metal spoon or silicone spatula, trying not to lose the volume
Pour into the tin, and spread the mixture around using a palette knife or the back of a spoon. Bake for 12 minutes
Remove from the oven and tip onto a clean sheet of baking paper
Remove the baking paper the sponge was baked with, then roll up the sponge, taking the clean baking paper with it, then leave to cool completely
Gently unroll the sponge (it may not unroll fully, so gently lift the curled over end up to add the filling) and spread a layer of melted Biscoff spread all over it. It's much easier to spread the Biscoff when it's melted, so pop it in the microwave for 10-20 seconds to melt it first
Whip up the cream with the icing sugar and vanilla until thick
Spread the double cream over the Biscoff spread
Re-roll the sponge as tightly as you can, and place onto a serving plate
Add the Biscoff spread to the cooled ganache and whisk in using an electric mixer. If the ganache is very thick and stiff, add the milk to loosen it
Spread the ganache over the yule log covering the sides and ends. Use a fork to create texture
Decorate with the crushed biscuit and white chocolate stars if using
Serve immediately, store leftovers in the fridge and eat within 2-3 days