Scotch Shortbread

Directions

1. 1
   Cream butter and add sugar.
2. 2
   Blend thoroughly.
3. 3
   Add egg yolk and vanilla.
4. 4
   Sift flour and baking soda and mix well with first mixture.
5. 5
   Spread in ungreased pan and then prick deeply with a fork.
6. 6
   Bake in a 250° moderate oven for 25 minutes or until golden brown.