Scottish Shortbread


4 cups all-purpose flour
1 cup icing sugar (aka confectioner's sugar)
1 cup butter, at room temperature

Beat butter until soft. Add sugar and beat until smooth. Add flour, one cup at a time. When completely mixed, knead by hand until smooth.

Roll out to 1/2 inch thick. Cut squares and place onto floured cookie sheet.

Bake at 300oF for 25-30 minutes, until firm to the touch.