01 - Set oven temperature to 400°F and allow to fully preheat.
02 - Fit the unbaked pie crust into a 9-inch pie pan, shaping or crimping the edges as desired.
03 - Pour 1 1/2 cups of water carefully into the prepared pie crust.
04 - In a mixing bowl, thoroughly blend 3/4 cup sugar with 3 tablespoons flour. Evenly sprinkle this mixture over the water in the crust.
05 - Drizzle 1 teaspoon vanilla extract over the surface and add a pinch of salt.
06 - Slice 4 tablespoons unsalted butter into thin pieces and distribute evenly on top.
07 - Place pie pan on the lower oven rack. Bake at 400°F for 30 minutes.
08 - Lower oven temperature to 375°F and continue baking for 20 minutes, until crust is golden and the filling is set with a slight jiggle.
09 - Carefully remove from oven. Cool the pie completely to room temperature, then refrigerate for at least 2 hours before slicing.