Preheat the oven to 300 degrees F (150 degrees C). Mix together flour, butter, and 1/2 cup sugar in a bowl with your hands until well combined. Press dough into an ungreased 11 ½ x 7 ½-inch sheet tray or jelly roll pan. Sprinkle with 1 tablespoon sugar. Bake in the preheated oven until edges…