Preheat oven to 275°F (135°C).
Cream butter, add sugar and blend thoroughly. Add vanilla.
Add flour in four portions and mix well after each addition.
Turn out onto flat surface and knead until all cracks have disappeared.
Roll dough into 1/2″ thick rectangles (or shape of choice) and cut cookies with a cookie cutter. Prick each cookie deeply with a fork.
Place on an ungreased pan and bake for 25 minutes or until light brown.
This cookie keeps well at room temperature or can be frozen.