1. Fill pie crust with two cups of blueberries, set aside.
2. In a sauce pan, crush remaining two cups of blueberries. Stir in sugar and cook over medium heat, stirring until sugar is dissolved.
3. In a separate dish, blend corn starch, water and lemon juice.
4. Add mixture to sauce pan with cinnamon. Cook, stirring until mixture boils and thickens.
5. Spoon mixture over blueberries in pie shell; refrigerate one hour.
6. Top with ice cream or whipped cream.

Enjoy!