In a medium bowl, whisk together the 1 1/4 cups (150g) of all-purpose flour and 1/2 teaspoon of salt. Scatter the cold, cubed 1/2 cup (113g) of butter over the flour mixture. Using a pastry blender or your fingertips, cut the butter into the flour until the mixture resembles coarse crumbs with some pea-sized pieces of butter remaining.

Drizzle 4 tablespoons (60ml) of ice water over the mixture. Gently toss with a fork until the dough starts to come together. If it's too dry, add more ice water, 1 tablespoon at a time. Do not overwork the dough. Form the dough into a disk, wrap it in plastic wrap, and refrigerate for at least 1 hour.

Preheat oven to 375°F (190°C). Roll chilled dough into a 12-inch circle and fit into a 9-inch pie dish. Trim, tuck, and crimp the edges. Prick the bottom with a fork and freeze for 15 minutes.

Toast pecan halves for 5-7 minutes. In a large bowl, whisk eggs, then whisk in dark corn syrup, dark brown sugar, melted butter, vanilla, and salt until smooth.

Arrange toasted pecans and chocolate chunks in the chilled pie crust. Pour the filling over the top.

Bake on a preheated baking sheet for 45-55 minutes, until the edges are set and the center has a slight jiggle. Shield crust edges with foil if they brown too quickly.

Let the pie cool completely on a wire rack for at least 4 hours before slicing and serving. This step is crucial for the filling to set.