In a bowl of a food processor add flour, butter, Parmesan cheese, rosemary and salt. Pulse until crumbly, but sticks together when pressed with fingers. Pour onto a floured pastry board and gather into a ball. Cover it with clingfilm and allow dough to rest in refrigerator for one hour.
Preheat oven to 180°C/gas mark 4.
Remove dough from the refrigerator and allow it to warm slightly, about 10 mins. Place rested dough on a lightly floured pastry board and roll out to 1cm thickness.
Line a baking tray with a silpat mat or baking paper. Using a 5cm biscuit cutter, cut out circles and place them on the baking sheet, 2 1/2cm apart. Gather dough scraps into a ball. Roll out leftover dough and cut additional circles. Continue until all the dough is used. If the dough becomes too soft and the butter starts to melt, place it back into the refrigerator to firm up again.
Place in oven and bake 8 to 10 mins or until golden brown.