Light and buttery shortbread cookies. They will melt in your mouth.
Thoroughly cream butter and sugar; add egg yolk and vanilla. Beat well. Add flour; mix well. May be dropped by the spoonful onto an ungreased cookie sheet; chilled and sliced; or rolled on a floured cloth and cut with cookie cutters. Bake at 350ºF for 10-15 minutes.
After baking, the mixture can be crushed and used to make a crumb crust for a pie.