1. Prepare Crust: Preheat oven to 350°. Pulse chocolate wafers in a food processor 8 to 10 times or until finely crushed. Stir together wafer crumbs, pecans, and butter. Press on bottom, up sides, and onto lip of a lightly greased 9-inch pie plate. Bake 10 minutes. Cool completely (about 30 minutes).
2. Prepare Filling: Whisk together sugar and next 2 ingredients in a large saucepan. Whisk together half-and-half and yolks in a large bowl. Gradually whisk egg mixture into sugar mixture; bring to a boil over medium heat, whisking constantly. Boil 1 minute, whisking constantly; remove from heat.
3. Microwave chocolate in a small bowl at HIGH 1 1/2 minutes or until melted, stirring at 30-second intervals. Whisk 2 Tbsp. butter and melted chocolate into sugar mixture; spoon into prepared crust. Place plastic wrap directly onto filling (to prevent a film from forming). Chill 4 to 24 hours. Top with Coffee Whipped Cream just before serving.