Sift together the flour, cinnamon and salt into a large bowl. Rub in the butter with a fork until mixture becomes crumbly. Add sugar and vanilla extract and mix to a stiff paste. Mix in egg. Knead dough on a floured surface until smooth. Wrap in foil or cling film and refrigerate for 30 minutes.
Preheat oven to 180 C. Grease baking trays. Roll out dough thinly and cut into 24 rectangles.
Bake 12 to 15 minutes or until lightly golden in colour. Let cool on wire rack.