Preheat oven to 160 degree celsius.
Cream butter and icing sugar till pale and fluffy.
Mix in vanilla.
Add in sifted plain flour and cornflour.
Fold the ingredients together with a spatula until it is well incorporated. Do not over mix.
Put the dough into a piping bag with 1M/star tip nozzle.
Pipe the cookies onto a baking tray. Leave a small gap between the cookies as they will expand a little during baking.
Top with sprinkles if desired.
Bake for 20-22 minutes or until the cookies turn light golden brown.
Leave it to cool on a cooling rack before storing them in air-tight container.