This recipe I think might be my new favorite for shortbread. It's the closest I've had yet to the shortbread I had in Scotland (they really know what they are doing there!)
1 cup powdered sugar
1 cup butter -softened
1 egg yolk
2 cups flour
1/2 cup cornstarch
In a large bowl, combine powdered sugar and butter. Beat until light and
Add egg yolk. Bend well.
Add flour and cornstarch. Mix well.
Divide dough in half. Shape each half into roll 12" long. Wrap in plastic
wrap. Press sides of roll with palm of hand to make 3 even sides, forming
triangular shape. Press roll against countertop to smooth and flatten sides.
Refrigerate 2 hours or until firm.
Heat oven to 350 degrees.
Cut dough into 1/4" slices. Place slices on ungreased cookie sheets. If
desired, sprinkle lightly with sugar.
Bake for 8-13 minutes or until set and light golden brown.
Prick tops of cookies with fork. Remove from cookie sheets.