Preheat oven to 350 degrees with rack in center. On a lightly floured surface, roll out pie dough to a 12-inch round, about 1/8 inch thick. Wrap dough around rolling pin, and unwrap over a 9-inch tart pan with a removable bottom. Press dough into bottom and up sides of pan; trim edge of dough.
In a large bowl, whisk together eggs, sugar, light corn syrup, 4 teaspoons melted butter, and the vanilla. Scatter chocolate evenly over tart shell. Pour filling over chocolate. Arrange pecans on top, as desired. Dot with 2 teaspoons chilled butter.
Place tart pan on a rimmed baking sheet. Bake until filling is set, 45 to 60 minutes. If pecans are browning too quickly, tent pan with foil. Remove from oven; while still hot, drizzle with bourbon, if desired. Let tart cool completely before serving.