Cream butter, sugar (and vanilla if using) together until light and fluffy.
Stir in sifted flour and lemon zest if using.
Bring together with your hands and squeeze together until you form a buttery dough.
Flatten your dough into a disc and wrap in baking parchment.
Chill for 10 minutes.
Lightly flour your surface and roll dough out to 1cm thickness.
Cut out your biscuits with a cookie cutter, re rolling trimmings and cutting out more until all dough is used.
Lay biscuits on your prepared baking trays and bake in the preheated oven for 15 - 20 minutes until just lightly browned.
Leave to cool on the trays for 2 minutes then transfer to a wire rack to cool completely.
To Decorate (optional)
Brush each cooled biscuit with a little lemon juice.
Sprinkle with lemon sugar.
Notes
Nutritional information is only an approximate guideline. Calculations will vary according to the ingredients you use and your cooking methods.These shortbread biscuits will store well for several days in an airtight tin.The biscuit dough can be frozen before baking.For further tips and tricks please see the body of my post.