Combine pastry flour and salt. Cut in cold butter until pea-size pieces remain, then add water gradually until the dough holds together.
Shape into a disc, wrap, and chill 1 hour. Roll into a 12-inch circle, fit into the pie plate, trim, and crimp the edge.
Chill the lined plate for 20 minutes while heating the oven to 350°F (175°C). Place a rimmed baking sheet on a lower-middle rack.
Whisk corn syrup, brown sugar, eggs, cooled melted butter, vanilla, and filling salt until well combined without beating in excessive foam.
Scatter pecans in the chilled unbaked shell. Pour filling over them slowly, allowing liquid to settle around the nuts.
Set the pie on the baking sheet. Bake 55–65 minutes, shielding the pastry edge if needed, until the outer filling sets and the center jiggles gently.
For a firmer doneness check, the center should reach about 200°F (93°C). Avoid baking until the whole surface is rigid or puffed dry.
Cool on a rack for at least 3 hours. Refrigerate once cool, then cut with a sharp knife, applying steady pressure through the pecans.
