In 1-cup microwavable measuring cup, microwave chocolate chips and shortening on High 30 seconds. Stir; continue microwaving, stirring every 10 seconds, until chocolate is melted and can be stirred smooth. Dip 1 end of each cookie halfway into melted chocolate, letting excess drip off. If desired, sprinkle additional toffee bits over chocolate. Place on waxed paper or cooking parchment paper until set.