陆 unwaxed lemon, zest only
125驳/4陆辞锄 caster sugar
40驳/1陆辞锄 ground almonds
icing sugar, for dusting
pinch salt
1 tsp vanilla extract
200g/7oz gluten-free plain flour, plus extra for rolling
125驳/4陆辞锄 unsalted butter, at room temperature
1 free-range egg, lightly beaten