2 1/3 cups all-purpose flour (spooned and levelled)
1/3 cup coarse or castor sugar or cake decorations for decorating to your taste!
In a food processor, combine butter, confectioners' sugar, and salt; process until smooth. Add flour and pulse just until combined. Form dough into an 8-inch-long round or square log; wrap tightly in plastic and freeze until firm, 30 minutes (or up to 1 month).
Preheat oven to 350 degrees, with racks in upper and lower thirds. Cut dough into 10cm thick slices. Dip edges in sugar if desired and transfer to two parchment-lined baking sheets. Bake until cookies are golden brown around edges, 15 to 18 minutes, rotating sheets halfway through. Let cookies cool 5 minutes on sheets. Transfer to wire racks to cool completely. Then decorate to your hearts content!