1 tbsp coffee granules, dissolved in 1 tablespoon of boiling water
陆 level tsp baking powder
225g/8oz caster sugar
225g/8oz icing sugar, sifted
225g/8oz self-raising flour
50驳/1戮辞锄 walnuts, finely chopped
8 walnut halves, to decorate
225g/8oz unsalted butter, softened, plus extra for greasing
125g/4陆oz unsalted butter, softened
4 large free-range eggs