Preheat oven to 160ºC (325ºF)

Sift the flour, cornflour and salt into a bowl.

Cut the butter into squares and beat with the icing sugar in a mixer for a minute or two until the icing sugar and butter are soft and well combined.

Beat in the vanilla extract and lemon oil.

Gradually add the flour mixture until just combined.  Do not overwork it.

Remove the dough and wrap in greaseproof paper.  Place in the fridge for at least an hour.

Roll the dough on a lightly floured board until it is about 1/4inch thick and cut into rounds with a cookie cutter.

Place on parchment on a baking sheet and bake for 15-20minutes depending on your oven until pale golden in colour.

Cool on a baking rack.

You spread some melted white chocolate with a few drops of lemon, onto one side of the cookie for a sweeter and more lemony flavour.