Sift flour and salt together.
Cream the butter, sugar and egg in a large bowl until creamy.
Add vanilla and sifted dry ingredients, and mix to form a stiff dough.
Wrap in plastic and chill until firm.
Roll out to ± 1/2 cm thick and cut into desired shapes. Place on a greased baking sheet.
Bake at 190° C(375°F) for 8-10mins or until lightly browned on the edges. Remove to cooling racks with a spatula and cool before decorating.
Ice with glace icing made by warming 250ml icing sugar (1cup) in a saucepan with a few drops of lemon juice, stirring well until it is a good spreading consistency.
If you want to hang the cookies from the tree, make a hole in the dough, using a plain nozzle, before baking.