For the shortbread, first mix sugar, flour, salt and butter to form a dough. Knead briefly on a floured work surface, then form into a roll. Wrap in plastic wrap and let rest in the refrigerator for about 60 minutes.
In the meantime, line a baking tray with baking paper. Preheat the oven to 170 °C top/bottom heat.
Unwrap the roll and cut slices about 1 cm wide. Alternatively, roll out the dough to a thickness of 1 cm and cut into rectangles with a knife.
Place on the baking sheet with enough space between them and prick with a fork. Put the shortbread in the oven for about 15 minutes.