01 - Set oven to 400°F. Position a rack on the lowest level.
02 - Press the unbaked pie crust into a 9-inch pie pan and crimp the edges for an attractive border.
03 - Pour 1 1/2 cups of water evenly into the prepared crust.
04 - In a mixing bowl, blend 3/4 cup granulated sugar with 3 tablespoons all-purpose flour until fully incorporated. Sprinkle this mixture uniformly over the water.
05 - Drizzle 1 teaspoon vanilla extract over the top and add a pinch of salt.
06 - Slice 4 tablespoons unsalted butter into thin pieces and arrange them evenly across the surface.
07 - Transfer the pan to the lower oven rack and bake for 30 minutes at 400°F.
08 - Lower the oven temperature to 375°F and continue baking for 20 minutes, or until the crust is golden and the filling has set with a gentle jiggle in the center.
09 - Remove the finished pie from the oven. Let it cool fully at room temperature, then chill for at least 2 hours in the refrigerator before slicing to achieve optimal texture.