1 double 9 inch pie shell
4 to 5 cups fresh or frozen blueberries
1/4 cup corn starch
2 tablespoons flour
1 1/4 cups sugar
2 drops vanilla extract
1 tablespoon lemon juice
1 tablespoon unsalted butter
egg wash (1 egg with a pinch of salt) for glazing

Preheat oven to 425 F.

Line a 9-inch pie pan with pastry dough .
In a large bowl, toss the blueberries, corn starch, flour, sugar, vanilla extract and lemon juice. Spoon or mound into pie shell. Dot with the unsalted butter. Wet pie edges with a bit of water. Roll remaining pastry to fit top of pie. Place on pie and press securely onto fruit and edges to seal. Trim edges and crimp. Cut slits for steam to escape. Brush top of pastry with egg wash.

Place pie on baking sheet and place on lowest rack in oven. Bake for 20 minutes, reduce heat to 375 F. and bake until juices begin to bubble through steam slits (about 35 to 45 minutes). Cool for 1 hour before serving.