Preheat the oven to 180'C.
Melt the chocolate in a heatproof bowl over simmering water (bain-marie).
Sift the flour, baking powder and cocoa powder together. In a bowl, beat the sugar and the butter together until the mixture is pale and fluffy. Beat the eggs into the butter mix one at a time. Gently incorporate the oil into the butter mix. Fold in the flour mix and then add the melted chocolate.
Pour the mixture into a cake tin and bake for 30 to 40 minutes. After about 30 minutes check the cake is cooked by inserting a skewer into the centre. If it comes out clean it is ready. Allow to cool and then transfer to a cooling rack for cutting and icing.
For the chocolate icing: Place the cream and the golden syrup into a saucepan and bring to the boil. Whisk in the cocoa powder. Bring back to boil the mix and simmer for 3 minutes. Allow to cool.
For the white chocolate filling: Melt the white chocolate over a bain-marie. Whisk the cream with the Amaretto until stiff. Fold the melted white chocolate through the whipped cream.
Cut the cake twice across the circumference halves. You should now have three sponges. Spread the white chocolate filling on two sponges. Place one on top of another and cover with the third piece. Coat the final layer with the chocolate icing and allow to set.
«When melting the white chocolate take care not to use excessive heat as it will burn and curdle. »