Preheat the oven to 180 °C.

Line a baking sheet with baking paper.

Sift the flour and salt together and set aside.

In the bowl of a stand mixer with the paddle attachment, combine the butter and castor sugar and beat until fluffy – about 5 minutes.

Add the flour to the butter mixture in three additions, beating until just combined each time. Form the dough into a ball, wrap in cling wrap and refrigerate for 30 minutes.

Roll the dough out on a lightly floured surface to about 3 mm thick. Cut out shapes with a cookie cutter and place on the prepared baking sheet.

Bake for 12-15 minutes, then remove from the oven. Allow the biscuits to cool on the tray for a few minutes before carefully moving to a cooling rack to cool completely.