1 (9 inch) pie shell, baked and cooled
1 banana, sliced
1 can blueberry pie filling
1 sm. container Cool Whip
1/4 c. sugar
3 tbsp. butter
3 tbsp. cornstarch

Pour blueberry pie filling into saucepan; add sugar, cornstarch, and butter. Cook on medium heat until butter melts and mixture becomes clear and thickened; set aside. Slice bananas into the cooled pie shell; pour the blueberry mixture over the bananas. Cool completely; decorate with cool whip. Keep refrigerated until served.