A delicious shortbread with a fruity spiral filling - both pretty and tasty.
Cream the butter and sugar - you can use a hand blender or a 'proper' mixer, both will work, or do by hand (in effect mashing them together).
Add flour and corn starch/cornflour and mix together but be careful not to overmix.
After chilling, carefully slice the log of dough into relatively thin slices and place on a lined baking sheet.
Bake for around 10-12min until just starting to brown. Allow to cool a minute before transferring to a cooling rack.
Note I recommend using weight measurements rather than cups for baking such as this.