175g/6oz caster sugar
25g/1oz cocoa powder, sieved, plus extra to dust
icing sugar, to dust
180驳/6录辞锄 dark chocolate (about 40% cocoa solids), broken into pieces
300驳/10陆辞锄 dark chocolate, broken into pieces
knob of butter, for greasing
150尘濒/5陆辞锄 double cream, whipped to soft peaks
300ml/陆 pint double cream
6 free-range eggs, separated
2 tbsp whisky