Heat oven to 350°F. Grease bottom and sides of jelly roll pan, 15 1/2x10 1/2x1 inch, with shortening, or line with aluminum foil. In large bowl, mix 1/2 cup brown sugar, 2/3 cup butter, 1/2 cup corn syrup, 1 teaspoon vanilla and the egg with spoon. Stir in flour and salt. Spread in pan. Bake 18 to 20 minutes or until light golden brown.