Serves: 30 to 36 crackers
Place the butter in the bowl of an electric mixer fitted with a paddle attachment and mix until creamy. Add the Parmesan, flour, salt, thyme and pepper and combine.
Dump the dough on a lightly floured board and roll into a 33cm long log. Wrap the log in cling film and place in the freezer for 30 minutes to harden.
Meanwhile, preheat the oven to 180C/Gas Mark 4.
Cut the log crosswise into 1/2 to 1 1/4-cm thick slices. Place the slices on a sheet pan and bake for 22 minutes.