Parmesan cheese straws

Place flour, cream of tartar, if using, cold butter (cut into 1 cm cubes), water and lemon juice in a food processor fitted with a steel blade. Process for 10 seconds.
Pat dough into a rectangle on a floured board. Fold in 2 short edges of pastry rectangle to meet at the centre, then fold dough in half (making 1 double fold). Rotate pastry 1/4 turn clockwise and repeat double fold. Wrap and refrigerate for 20 minutes.
Roll out pastry into a 40 cm square and freeze for 10 minutes to firm. Trim edges, brush with beaten egg and sprinkle with Parmesan cheese. Pat in cheese. Turn dough over and repeat.
Halve pastry, cut into 1,5 cm wide strips and twist strips into corkscrews. Place on a non-stick baking sheet, and press ends of cheese straws down firmly to prevent unwinding. Freeze until firm (10 minutes).
Bake at 190 ºC for 15 to 20 minutes, or until golden brown.