50驳/1戮辞锄 plain flour
70g/2陆oz golden caster sugar
1 tsp good quality cocoa powder, sifted, plus extra to decorate
50驳/1戮辞锄 dark chocolate (minimum 70% cocoa solids), broken into pieces
50驳/1戮辞锄 unsalted butter, plus extra for greasing
ice cream or cream, to serve
1 large free-range egg
1 large egg yolk