Cook 1 cup blueberries and 2/3 cup water until begins slow boil. Then mash with potato masher.
Mix 3 tablespoons cornstarch and 1 cup sugar. Add to blueberry sauce and cook until shiny and thick. Stir frequently. Set aside to cool.
Prepare and bake pastry shell. Cool until crust is still slightly warm.
Spread softened cream cheese evenly over warm crust. Add 2 1/2 cups blueberries to cooled blueberry sauce. Pour on top of cream cheese. Garnish filling with remaining blueberries.