In a saucepan, stir together 1/2 cup sugar, the 3 tablespoons cornstarch, and the cinnamon. Stir in the blueberries and orange juice. Cook and stir until mixture is bubbly. Cover and set aside.
For custard, in saucepan, combine milk, yolks, 1/2 cup sugar, the 2 tablespoons cornstarch, and the salt. Cook and stir until bubbly. Cook and stir for 2 minutes more. Stir in extract. Cover and set aside.
For meringue, in a medium mixing bowl, beat egg whites and cream of tartar until soft peaks form. Gradually add the 6 tablespoons sugar, beating until stiff peaks form.
Pour berry mixture into Baked Pastry Shell. Carefully spread custard evenly over blueberry mixture. Spread meringue over custard, spreading to edge to seal.
Bake the meringue-topped pie in a 350 degree F oven for 15 minutes. Cool on a wire rack. Store in the refrigerator. Makes 8 servings.