combine sugar and salt in a small bowl. Sprinkle some of the sugar mixture over a clean work surface, then place the puff pastry on top. Roll chilled pastry into a rectangle approx. 0.5-cm/0.25-inch.-thick, pressing the sugar into the dough. Sprinkle remaining sugar over the pastry, then lightly roll the pin over the sugar to press into the dough.
Starting from the long side, roll the dough up tightly like a carpet, stopping halfway. Repeat from the other side so that the two rolls meet. Carefully press the dough together along the seam to seal, then wrap in plastic and chill for approx. 30 min.
Preheat oven to 200°C/400°F. Slice the dough into approx. 0.5-cm/0.25-inch. pieces, then arrange on a baking sheet with space in between each cookie. Bake the cookies for approx. 10 – 15 min. at 200°C/400°F, flipping halfway, or until deeply caramelized on both sides. Watch them carefully towards the end of baking to ensure the sugar doesn’t burn. Transfer to a cooling rack and let cool completely before serving. Enjoy!