For the sponge:
125g caster sugar
2 tsp vanilla extract
125g self-raising flour
Pinch of salt
40g butter, melted
For the syrup:
75ml strong coffee, hot
1tbsp demerara sugar
2tbsp coffee liqueur
For the filling:
4 egg yolks
50g caster sugar
125ml Marsala wine
80g white chocolate, melted
500g mascarpone cheese
100g dark chocolate, grated
100g amaretti biscuits, crushed
Preheat the oven to 180C/160C fan. Grease and line 4 8cm cake tins.
Add the eggs, caster sugar and vanilla to the bowl of a stand mixer, whisk on high until the mixture is light and fluffy, it can take 6-8 mins.
Sift the flour, and salt and add a little at a time into the egg mixture and very gently fold into the egg mixture using a large metal spoon. When all the flour has been incorporated, gently fold in the melted butter Be careful not to knock out the air.
Divide the batter between the 4 tins, spread level and bake for 8-10 mins, an inserted skewer should come out clean. leave to cool for a few mins in the tin then turn out onto a cooling rack
To make the coffee syrup:
Pour coffee into a bowl and dissolve the demerara sugar into it. Once the syrup has cooled slightly add the coffee liqueur to taste.
For the filling:
Bring a pan of water to simmer.
In a heatproof bowl mix the egg yolks, sugar, marsala and a pinch of salt, place over the pan of simmering water and whisk for 3-4 mins with an electric hand mixer, the mixture should be thick and look around tripled in volume.
Remove the bowl from the heat and place in a bowl of cold water, continue whisking until the mixture is cold.
4 Beat the mascarpone cheese until it is smooth, fold into the egg mixture, then fold through the melted white chocolate once it is slightly cooled.
Place one cake layer in the bottom of an 8-inch springform tin, brush with the coffee syrup and spread over approx 2-3 tbsps of the filling mix. Scatter with 1 tbsp of the grated chocolate. Repeat with the second and third layers of cake, top with the fourth cake layer, cover with cling film and refrigerate overnight. Refrigerate the leftover filling mixture.
The next day remove the cake from the tin and use the remaining filling mix to cover the top and sides of the cake.
Press the crushed amaretti biscuits onto the sides and dust the top with the cocoa powder.