Sift baker's flour and cornflour into a large bowl.

In a separate bowl, beat butter until soft.

Add vanilla and caster sugar to the butter and beat until light and fluffy.

Press the mixture into a shortbread mould or roll out and cut into desired shapes (e.g., stars).

Alternatively, shape dough into a flat round. Pinch the edges with your fingers, prick the top of the round with a fork, and lightly score into 8 segments.

Place onto baking paper on an oven tray and sprinkle with extra sugar.

Bake at 150C (300F) for 15-20 minutes, or until a light golden colour.

If shaped into a round, cut the shortbread when warm to prevent crumbling.

When cool, dust with icing sugar.