Whisk the flour, sugar, and salt. Cut in the cold butter until pea-size pieces remain.
Add 3 tablespoons ice water and toss. Add more water, 1 tablespoon at a time, just until the dough holds together.
Shape the dough into a disk, wrap it, and chill for at least 1 hour.
Roll the dough into a 12-inch circle and fit it into a 9-inch pie plate. Trim, fold, and crimp the edge. Chill for 30 minutes.
Heat the oven to 375°F. Line the crust with parchment and fill it with pie weights. Bake for 15 minutes.
Remove the weights and parchment. Bake for another 5 to 7 minutes, until the bottom looks dry. Cool for 10 minutes. Lower the oven to 350°F.
Whisk the pumpkin, brown sugar, cornstarch, spices, and salt until smooth. Gently whisk in the eggs, evaporated milk, maple syrup, and vanilla.
Set the crust on a rimmed baking sheet and pour in the filling.
Bake at 350°F for 45 to 55 minutes. Shield the crust edge if it browns too quickly. The edges should be set and the center should wobble gently.
Cool on a wire rack for at least 3 hours before slicing. Refrigerate after cooling.