Line a baking sheet with parchment paper; set aside. Place chocolate in a small heat-proof bowl set over a pan of simmering water, and stir until melted. Remove bowl from heat; let chocolate cool, stirring occasionally, until it registers 88 degrees on a candy thermometer. Pour onto prepared baking sheet, and spread evenly with an offset spatula. Refrigerate until firm but still pliable, 8 to 10 minutes. Tear into jagged pieces, no larger than 1 1/2 inches each. Refrigerate until firm, about 15 minutes. Use immediately.