Shortbread Cookies

Shortbread Cookies

3/4 pound unsalted butter, at room temperature 1 cup sugar, plus extra for sprinkling 1 teaspoon pure vanilla extract 3 1/2 cups all-purpose flour 1/4 teaspoon salt 6 to 7 ounces very good semisweet chocolate, finely chopped Preheat the oven to 350 degrees F.In the...