3 large lemons, juice and finely grated zest
280g/10oz caster sugar
225g/8oz caster sugar
icing sugar, for dusting
50g/1戮 oz shelled pistachio nuts, finely chopped
100驳/3陆辞锄 butter, softened
300ml/10fl oz double cream, lightly whipped
5 free-range egg whites
5 free-range egg yolks