In small deep microwavable bowl, microwave chocolate chips and shortening uncovered on High 1 to 2 minutes, stirring every 30 seconds, until mixture can be stirred smooth. Dip each cookie halfway into melted chocolate, letting excess drip off. Place on parchment or waxed paper; sprinkle with remaining toffee bits. Let stand about 1 hour or until chocolate is set. To quickly set chocolate, refrigerate cookies 15 minutes. Store between sheets of parchment paper in tightly covered container at room temperature.