Grease a 9-inch pie plate. In a food processor, pulse together all-purpose flour, sea salt, and granulated sugar until combined. Add the cold, cubed unsalted butter and pulse until the mixture resembles coarse crumbs. Gradually add ice-cold water until the dough just starts to clump together. Form the dough into a disk, wrap it in plastic wrap, and chill for 1 hour.

Roll the dough on a lightly floured surface into an 11-inch circle. Transfer it to the greased pie plate, trimming excess dough and crimping the edges. Chill the crust again for about 20 minutes. Preheat oven to 350°F, line the crust with parchment paper, fill with pie weights, and blind bake for 15 minutes. Remove the weights and bake for an additional 5 minutes.

In a microwave-safe bowl, microwave the cubed unsalted butter and dark chocolate until smooth. In a separate bowl, whisk together dark brown sugar, granulated sugar, Dutch-process cocoa powder, cornstarch, and sea salt. Incorporate heavy cream, pure vanilla extract, and room temperature eggs, then stir in the melted chocolate.

Lower oven temperature to 325°F and pour the filling into the pre-baked crust. Bake for 50-55 minutes until edges are set but the center remains slightly wobbly. Cover the edges with foil if they brown too quickly.

Remove the pie from the oven and let it cool to room temperature on a wire rack for about 2 hours.