Yum-Yum Pie 1 graham cracker pie crust 2 c. blueberries 1/2 c. sugar 1 T. cornstarch 1 small carton Cool Whip 8 oz. cream cheese   Mix blueberries, sugar and cornstarch;  cook until thickened.    Cool.  Soften cream cheese and mix with Cool Whip.  In crust layer cream cheese mixture, blueberries and cream cheese mixture.  Garnish with graham cracker crumbs.  Cool