Pre-heat your oven to 355°F/ 320°F fan forced (180°C/ 160°C).
Grease and line the cake pan.
Sift the flour and corn flour together three times. This helps ensure a light fluffy sponge.
Beat the butter, sugar and vanilla together
Add the eggs one at a time, mixing well between each addition.
Add half the flour and corn flour in the butter and sugar mix. Fold in gently.
Add the milk, fold in gently.
Add the rest of the flour and corn flour, fold in gently. You want to make sure its all mixed together properly, but be gentle with the mix.
Transfer to lined cake tin and bake for 30 minutes or until starting to go golden brown.
Remove from oven and allow to cool completely and at least ten minutes before removing from the tin.
Cut cake into squares. Transfer back to cake tin and freeze for one hour.