Combine the flour, sugar, and salt in a large bowl. Add the butter and mix with a pastry blender or a fork until the largest pieces of butter are the size of large peas. (You can also pulse in a food processor.) Add the water, about a tablespoonful at a time, and mix just until a dough forms. 

Shape the dough into a ball, and then flatten into a disk about 1-inch thick. Wrap tightly in plastic wrap and refrigerate at least 2 hours. 

Place the chilled dough on a lightly floured surface. Roll the dough into a circle 1/8-inch thick. Transfer the dough to a 9-inch pie pan. Trim and crimp the edges as desired. Place the pan in the refrigerator while you prepare the filling. 

Place the butter, sugar, milk, eggs, and vanilla in a large mixing bowl. Stir until thoroughly combined. Stir in the cornmeal and salt. 

Transfer the filing to the crust. Bake for 55 to 60 minutes, or until the crust is golden brown and the filling is set with a slight jiggle in the center. Cool completely before serving.