01 - Set oven temperature to 400°F.
02 - Press the unbaked pie crust into a 9-inch pie pan and crimp the edges.
03 - Pour 1 1/2 cups water directly into the prepared pie crust.
04 - In a mixing bowl, blend 3/4 cup sugar with 3 tablespoons flour until evenly mixed.
05 - Sprinkle the sugar-flour mixture evenly over the water in the pie shell.
06 - Drizzle 1 teaspoon vanilla extract across the surface and add a pinch of salt.
07 - Slice 4 tablespoons butter into thin pats. Distribute evenly on top of the filling.
08 - Set pie on lower oven rack. Bake for 30 minutes at 400°F.
09 - Lower oven temperature to 375°F and bake for an additional 20 minutes until the crust is golden and the filling is softly set.
10 - Remove pan from oven and allow to cool to room temperature. Chill in the refrigerator for at least 2 hours before slicing.