1 tsp baking powder
90g/3¼oz light brown sugar
2 tbsp cocoa powder
pinch salt
70²µ/2½´Ç³ú self-raising flour
50ml/2fl oz sunflower oil, plus extra for greasing
75²µ/2â…”o³ú dark chocolate, broken into pieces
40²µ/1½´Ç³ú white chocolate, broken into pieces
3 tbsp double cream
1 large free-range egg
1 tsp espresso coffee powder