fresh blueberries or blackberries, to serve (optional)
5 large lemons, 2 zested, all juiced to make 250ml/9fl oz juice
275驳/9戮辞锄 plain flour
50驳/1戮辞锄 plain flour
400g/14oz caster sugar
100驳/3陆辞锄 icing sugar
200g/7oz salted chilled butter, cubed
6 free-range eggs