01 - Set oven to 400°F and allow it to fully preheat.
02 - Position unbaked pie crust evenly in a 9-inch pie pan, crimping edges if desired.
03 - Pour 1 1/2 cups water into the prepared pie crust.
04 - In a mixing bowl, blend 3/4 cup sugar and 3 tablespoons flour until homogenous. Sprinkle evenly over the water in the pie shell.
05 - Drizzle 1 teaspoon vanilla extract atop the mixture and season with a pinch of salt.
06 - Slice 4 tablespoons butter into thin pats and arrange them uniformly across the surface.
07 - Place pie on the lower oven rack. Bake for 30 minutes at 400°F.
08 - Reduce oven temperature to 375°F. Continue baking for 20 minutes, until the crust becomes golden and filling firms up with a slight jiggle at the center.
09 - Remove pie from oven and allow to cool fully to room temperature. Refrigerate for a minimum of 2 hours prior to slicing to ensure optimal texture.