In a medium saucepan, stir together the 1/2 cup sugar and the cornstarch. Stir in the fresh or frozen blueberries and water. Cook and stir the mixture over medium heat until thickened and bubbly. Cook and stir for 2 minutes more. Remove the saucepan from the heat. Cover and let the mixture cool.
In a medium mixing bowl, stir together graham cracker crumbs and melted butter until combined. Set aside 1/2 cup of the crumbs for topping. Press the remaining graham cracker crumbs into the bottom of a 13x9x2-inch (3-quart rectangular) baking dish.
In a mixing bowl, beat the softened cream cheese, the 1-1/2 cups sugar, and the vanilla until combined. Gently fold in the whipped cream.
Spoon half of the cream cheese mixture over the graham cracker crust. Spoon the cooled blueberry mixture over the cream cheese mixture. Spoon the remaining cream cheese mixture over blueberries.
Sprinkle the top of the dessert with reserved graham cracker crumb mixture. Cover and chill for 2 to 24 hours. Makes 12 servings.