Position oven rack in bottom third of oven. Preheat oven to 400°F (200°C).

On a lightly floured surface, roll All-Butter Pie Dough into a 12-inch circle (about ⅛ inch thick). Transfer to a 9-inch pie pan, pressing into bottom and up sides. Trim excess dough to ½ inch beyond edge of pan, if needed. Fold edges under, and crimp as desired. Freeze until firm, about 15 minutes.

In a large bowl, whisk together sugar, flour, and salt. Whisk in eggs, melted butter, and 1 teaspoon (4 grams) vanilla until combined. Whisk in buttermilk. Stir in chopped coconut. Pour into prepared crust.

Bake for 18 to 20 minutes. Loosely cover with foil, and reduce oven temperature to 350°F (180°C); bake until edges are set but center still has a slight jiggle and an instant-read thermometer inserted in center registers 200°F (93°C), 40 to 45 minutes more. (The pie may puff when removed from the oven and then deflate slightly as it cools.) Let cool completely on a wire rack. Refrigerate until ready to serve.

Just before serving, in a medium bowl, whisk together cold cream and remaining ½ teaspoon (2 grams) vanilla until thickened and medium-stiff peaks form.

Spoon onto pie, and garnish with toasted coconut, if desired. Refrigerate in an airtight container for up to 3 days.

In the work bowl of a food processor, pulse flour and salt until combined. Add cold butter, and pulse until mixture is crumbly and butter pieces are pea-size. With processor running, add ¼ cup (60 grams) ice water in a slow, steady stream just until dough comes together. (Mixture may appear crumbly. It should be moist and hold together when pinched.) Add more ice water if needed.

Turn out dough onto a clean surface, and shape into a disk. Tightly wrap in plastic wrap. Refrigerate for at least 1 hour or up to 2 days. Let dough stand at room temperature for 10 to 15 minutes before rolling if refrigerating for longer than 1 hour.