Preheat oven to 375°.

Sprinkle chocolate morsels and pecans into bottom of baked Buttermilk Piecrust. In a large bowl, whisk together brown sugar, flour, and salt. Add corn syrup, 3 tablespoons bourbon, melted butter, and eggs; whisk until smooth. Pour bourbon mixture over pecans. Loosely cover edge of piecrust with foil.

Bake for 30 minutes. Remove foil; bake until set, about 15 minutes more, loosely covering filling with foil to prevent excess browning, if necessary. Let cool completely on a wire rack. Refrigerate until firm, about 6 hours. Brush with remaining 1 tablespoon bourbon, if desired. Serve with ice cream.

Preheat oven to 425°.

In a medium bowl, stir together flour, salt, and sugar. Using 2 forks or a pastry blender, cut in butter until mixture is crumbly. Add buttermilk, 1 tablespoon at a time, stirring until a dough forms. Turn dough out onto a lightly floured surface; shape into a disk. Cover tightly with plastic wrap and refrigerate until firm, at least 30 minutes. Let stand at room temperature until slightly softened, 20 to 30 minutes.

On a lightly floured surface, roll dough into a 12-inch circle. Transfer dough into a 9-inch pie plate. Trim excess crust to extend 1⁄2 inch beyond edge of pie plate. Tuck edges under, and crimp as desired. Top with a piece of parchment paper, letting ends extend over edges of plate. Add pie weights.

Bake until edges of crust are lightly browned, about 10 minutes. Remove from oven. Carefully remove paper and weights. Let cool on a wire rack for 30 minutes.