Allow 30 mins rest time
This is a lovely buttery shortbread that gets a boost of flavour from fresh lemon zest.
Place the flours, butter, sugar, zest and salt in an electric mixer with paddle attachment and beat until well combined.
Turn mixture out onto a work surface and lightly knead together until you have a soft dough.
Wrap in plastic and pop in the fridge for half an hour to rest.
Now preheat your oven to 180C and line two baking trays with parchment paper.
Lightly flour your bench and roll out the dough until about 5mm thick, cut into shapes and transfer to baking trays.
Bake for about 10 minutes or until the biscuits are lightly golden.
Sprinkle with the extra golden caster sugar as soon as they come out of the oven then let cool on a wire rack. Makes about 20.