Preheat the oven to 400° F and roll out your pie crust. Place pie crust in 9in pie plate.
Pour the water into the unbaked crust.
Mix the flour, sugar, and spices together in a separate bowl. Sprinkle this mixture over the water and swirl if desired, but do not completely combine.
Drizzle the 2 tbsp of vanilla over the filling. Do not stir.
Place the 5 pieces of butter evenly over the pie.
Bake in the oven for 30 minutes. After this, reduce the baking temperature to 375°F and cover the crust with foil. Bake another 30 minutes.
Remove the pie from the oven and let cool completely. It will still be a little watery when removed, but like a custard pie it will solidify more as it cools.
After it cools, refrigerate for at least 3 hours before serving.