1. Mix the butter and sugar together until pale and fluffy
2. Sift the flour and cornflour into the mixture.
3. Mix together thoroughly and knead until a consistent, pale, golden colour forms.
4. Score and prick with a fork.
5. Place in the fridge for 25 mins and then into an 8x8 baking tray. Place in a 180° oven for 15 – 20 minutes. Remove before it starts to brown.
6. Sprinkle with extra caster sugar.
7. Allow to cool on a wire rack until it becomes hardened and slightly crispy.
8. Serve with cream or jam!