1 tsp baking powder
90g/3录oz light brown sugar
2 tbsp cocoa powder
pinch salt
70驳/2陆辞锄 self-raising flour
50ml/2fl oz sunflower oil, plus extra for greasing
75驳/2鈪攐锄 dark chocolate, broken into pieces
40驳/1陆辞锄 white chocolate, broken into pieces
3 tbsp double cream
1 large free-range egg
1 tsp espresso coffee powder