How to Make It
Prepare the Vanilla Bean Custard Sauce: Whisk together egg yolks, granulated sugar, and kosher salt in a medium bowl until very smooth. Set aside.
Split vanilla bean open lengthwise, and scrape out seeds into a medium saucepan. Add half-and-half, and cook over medium, whisking vigorously, to disperse seeds into milk and until small bubbles form around edges of pan and mixture is very hot but not quite boiling. Remove from heat.
Whisking constantly, gradually pour 1/4 cup hot half-and-half mixture into egg yolk mixture. Continue whisking hot half-and-half mixture into egg yolk mixture, 1/4 cup at a time, until completely combined. Transfer mixture to saucepan, and place over low heat.
Cook, whisking constantly, until custard thickens enough to coat the back of a spoon and your finger leaves a clear line when drawn through the custard, 20 to 25 minutes. (Do not allow it to boil, or it will curdle.) Immediately remove from heat, and quickly pour through a fine wire-mesh strainer over a medium bowl. Discard solids in strainer.
Let custard cool 10 minutes, stirring occasionally. Place plastic wrap directly on the custard (to prevent a film from forming). Refrigerate until very cold, at least 4 hours or overnight. (It will thicken as it chills.)
Prepare the Crust: Preheat oven to 375°F. Unwrap chilled pie dough disks from Double-Crust Pie Pastry, and place on a lightly floured surface. Let stand at room temperature until slightly softened, about 5 minutes. Sprinkle each disk with flour, and roll into 12-inch circles. Carefully fit 1 dough circle into a 9-inch deep-dish glass pie plate; fold edges under, and press to flatten.
Cut the remaining disk into 1/4-inch strips. Braid the strips, 3 at a time. Using a pastry brush, brush a little water around the entire edge of the bottom crust. Gently press the braided strips to the moistened edge to adhere. Line pastry with parchment paper, and fill with pie weights or dried beans.
Bake in preheated oven 15 minutes. Transfer to a wire rack, and remove pie weights and parchment. Cool 30 minutes. Increase oven temperature to 450°F.
Prepare the Cushaw Filling: Stir together sugar, ginger, kosher salt, and nutmeg in a small bowl. Whisk together roasted cushaw puree, heavy cream, honey, and eggs in a medium bowl until thickened and smooth. Stir in sugar-spice mixture until incorporated. Pour filling into prepared piecrust.
Bake at 450°F for 10 minutes. Reduce oven temperature to 325°F. Bake until edges puff up and center is almost firm, wiggling only slightly in center when you gently nudge pie plate, about 30 minutes. Transfer to a wire rack, and cool to room temperature, about 2 hours. Sprinkle with chopped candied pecans, if desired. Serve with Vanilla Bean Custard Sauce.