Pre-heat oven to 165°C (fan-forced)
In a stand mixer, combine the butter and sugar to form a paste.
Add the cornflour and flour, then mix on low until it just comes together.
Divide the dough into 3 equal balls
On a lightly floured surface, roll each dough ball into a disc, about 1 cm thick. Each disc should be around 15cm diameter. Place onto a lined baking tray.
Using your thumb and forefinger, pinch around the edges of the discs to create a pattern.
Using a large knife, gently press lines into the discs, to create 8 portions.
Bake for 14 minutes, until lightly golden. Cool on tray for 5 minutes, before transferring to a cake rack.