Combine flour and salt in a large bowl. Cut in the cold butter using a pastry blender or your fingertips until pea-sized lumps remain. Drizzle in 3 tablespoons ice water, tossing until the dough just comes together, add the last tablespoon only if needed. Flatten into a disc, wrap, and chill for at least 1 hour before rolling.
Roll the chilled dough on a floured surface to a 12-inch circle and line a 9-inch standard pie plate. Trim and crimp the edges. Freeze the shaped crust 15 minutes, then line with parchment, fill with pie weights, and bake at 400°F (200°C) for 15 minutes. Remove weights, bake another 7-10 minutes until just golden. Cool completely.
Spread pecans in a single layer on a baking sheet and toast at 350°F (177°C) for 7-9 minutes, stirring once, until fragrant and a shade deeper. Watch closely to avoid burning. Cool to room temperature before using in the filling; this step deepens flavor and preserves texture.
In a large bowl, whisk together the brown sugar, corn syrup, eggs, melted cooled butter, vanilla, and salt until smooth and homogenous. Stir in the toasted pecans until evenly combined, reserving a few pecan halves for arranging on top if you want a decorative finish.
Reduce oven to 350°F (177°C). Set the cooled crust on a rimmed baking sheet (for easy transfer). Pour the filling into the shell and, if desired, neatly arrange reserved pecan halves on top. Bake 40-50 minutes, turning halfway through, until edges are set and the center gently wobbles when the pie is jiggled, like set gelatin.
Let the pie cool on a wire rack for at least 3 hours, do not slice sooner, or the filling may ooze. The pie is ready when the filling is fully set and slices hold their shape. Serve at room temperature for best texture and flavor, with or without whipped cream.