Cook over med heat blueberries and water until it comes to a boil. Add sugar and bring back to a boil again. Thicken with cornstarch. Set aside to cool.

Cut together flour and butter, add 3 to 5 Tbs ice water for pie crust. Press lightly in 9 x 13 pan. Bake at 350°F for 15 min. COOL.

Mix cream cheese, sugar and vanilla. Add Cool Whip. Spread carefully over crust. Top with cooled blueberry mixture. Refrigerate