From Farm Journal's "Complete PIE Cookbook"
Baked 9" Pie Shell (see "Pie Crust", below.)
3/4 Cu. Sugar
Whipped Cream (optional)
Combine sugar, cornstarch and salt in a saucepan. Add water and 2 Cups Blueberries; cook over medium heat, stirring constantly, until mixture comes to a boil and is thickened and clear. (Mixture will be quite thick.)
Remove from heat and stir in butter and lemon juice. Cool.
Place remaining 2 cups raw blueberries in pie shell. Top with cooked berry mixture. Chill. Serve garnished with whipped cream.