Preheat oven to 400° Fahrenheit. Set empty pie crust on a lined baking sheet.
Pour 1 + 1/2 cups water into the pie crust
In a small bowl, whisk together flour and sugar. Sprinkle evenly over water in crust. DO NOT STIR.
Drizzle vanilla or almond extract over water in pie crust. Place pats of butter on top of water mixture.
Bake at 400 for 30 minutes. Reduce heat to 375 and cover sides of crust, or create a foil tent to go over top of the pie, if needed to prevent burning. Continue baking for an additional 30 minutes.
Pie will be VERY watery when you pull it out of the oven but will gel as it cools. Allow to cool completely, then cover and place in the refrigerator until chilled before cutting.
To make the raspberry sauce, place 1 pint of raspberries and sugar into a medium sauce pan, over medium heat. Mash raspberries with a rubber spatula and bring mixture to a low boil stirring occasionally. Add vanilla or almond extract. Stir.
Place a wire strainer over a small bowl. Pour raspberry mixture through a strainer, pushing it back and forth with a spatula until only the seeds and thick pulp remain.
Pour raspberry sauce in a container and chill until ready to drizzle over pie.