Double-crusted blackberry pie

Blackberries	4 cups
Sugar	¾ cup
Powdered pectin	2 tablespoons
Water, cold	½ cup
Vanilla bean	1
Butter, softened	2 tablespoons
Flour	¼ cup
Pie dough	1
Egg	1
Milk	2 tablespoons

1. Place the blackberries, sugar, pectin, and water into a medium saucepan.
2. Split the vanilla bean in half lengthwise, and scrape the seeds into the saucepan; add the pod to the pan.
3. Bring the berries to a boil over medium-high heat, stirring frequently.
4. Reduce the heat to moderate, and simmer, stirring occasionally, until the juices thicken enough to coat the back of the spoon, about 30 minutes.
5. Remove the pan from the heat, and let the mixture rest for 30 minutes or so.
6. Preheat oven to 375°F.
7. Grease a 9-inch ceramic or glass pie pan with the butter, and dust it with some of the flour.
8. Roll two-thirds of the pie dough out on a lightly floured surface to a ¼-inch thickness.
9. Fit the dough into the prepared pan, and trim off any excess dough from the edges.
10. Remove the vanilla bean pod from the cooled filling, and discard; pour the filling into the prepared pie shell.
11. Roll the remaining third of pie dough out on a lightly floured surface to a ¼-inch thickness, and lay it over the berry filling.
12. Crimp the edges of the dough together, and make a few slits through the top crust to allow steam to escape while baking.
13. Bake the pie for 30 minutes.
14. Beat the egg and milk together in a small bowl, then brush the top crust of the continue to bake it until the crust is a deep golden brown, about 15 minutes more.
15. Transfer the pie to a wire rack to let cool until it is just warm or room temperature; serve with ice cream.

Recipe from My New Orleans The Cookbook by John Besh.