Gran's Scottish Shortbread

Submitted by the Cafe's host himself, Sam/copperbadge. From the Cafe Cookie Book.

• Ready In: 45 mins
• Serves: 16
• Yields: 16 wedges

Ingredients

• 1  cup unsalted butter, softened
• 1⁄2 cup confectioners' sugar
• 1  egg yolk
• 1⁄4 teaspoon salt
• 2 1⁄4 cups flour

Directions

1. Beat butter with sugar, salt, and egg yolk until fluffy.
2. Add flour a little at a time until mixture is too stiff to work with a spoon. (Do not use a mixer, as the dough will be far too stiff.)
3. Flour a counter or board and knead the dough, pulling the flour into it, until it just begins to "crack". It's about the texture of play-doh at this point, perhaps a little stiffer. You may need a little more or a little less than 2 1/4 cups.
4. Divide the dough into two balls and pat them each into a circle about 1/2 inch thick on an ungreased cookie sheet. Prick the whole thing with a fork, and use the flat of the fork to press lines around the edges.
5. Bake at 350°F until brown, about 30 minutes. The center will be a pale pastel yellow and the edges will just be turning brown.
6. Remove the cookie sheet and cut the shortbread while it's still hot (it gets more brittle as it cools).