Roll out the pastry into a rectangle on a lightly floured surface to fold a palmier. Sprinkle a generous amount of sugar on top, then fold the two shorter sides of the rectangle towards the center, leaving a small gap in the middle. Sprinkle more sugar on top of the folded dough, then fold the dough in half along the center gap, pressing down lightly to seal. Repeat the process by folding the dough in half again, then wrap it in plastic wrap and chill it in the refrigerator before slicing it into individual cookies.