400g/14oz smooth peanut butter (the regular kind, not a health-store variety)
225g/8oz plain flour
1 tsp baking powder
陆 tsp bicarbonate of soda
100g/3陆oz soft dark brown sugar
125驳/4陆辞锄 caster sugar
50驳/1戮辞锄 cocoa powder
600g/1lb 5oz icing sugar
30g/1oz dry roasted peanuts, chopped, to decorate
陆 tsp fine sea salt
2 tsp vanilla extract
200g/7oz unsalted butter, plus extra for greasing
300g/10陆oz unsalted butter, softened
120ml/4fl oz double cream
2 large free-range eggs, at room temperature