01 - Preheat oven to 400°F. Place the unbaked pie crust into a 9-inch pie pan and crimp the edges as desired.
02 - Pour water directly into the pie crust.
03 - In a small bowl, blend granulated sugar and all-purpose flour until combined. Evenly sprinkle over the water in the pie crust.
04 - Drizzle vanilla extract over the filling and add a pinch of salt. Slice butter into thin pats and distribute evenly atop the surface.
05 - Carefully transfer the pie to the lower oven rack and bake for 30 minutes at 400°F.
06 - Reduce oven temperature to 375°F and continue baking for 20 minutes, until the crust is golden and the filling gently jiggles in the center.
07 - Remove pie from oven and allow to cool entirely at room temperature. Refrigerate for at least 2 hours prior to slicing for optimal set.