In a saucepan, gently stir together the berries and one cup sugar and 1/4 cup water over low heat on stovetop. Simmer for about 10 minutes; stirring occasionally, or until berries are softened.
In small mixing bowl, stir cornstarch and remaining 3 tablespoons water together until smooth. Pour cornstarch into simmering blueberry mixture and gently stir over low heat until it thickens. Take mixture off heat and allow to cool completely.
Preheat over to 350 degrees. To make the crust: Pour flour and pecans into a bowl of food processor. Place butter, 1 tablespoon at a time, evenly over the top of dry ingredients and pulse just until butter becomes incorporated through. (Can also be done by using a pastry cutter).
Put mixture into a 9 x 13" baking dish and press evenly along bottom of pan to form the crust. Bake for 20 minutes and allow to cool completely.
In large mixing bowl, whip cream, using electric mixer set on medium speed until stiff peaks are just about to form. Do not overbeat. Set aside.
In separate bowl, beat together cream cheese and remaining 1 cup sugar until smooth using electric mixer on medium speed.
Using a rubber scraper, gently fold whipped cream into cheese mixture and spread over cooled crust. Pour thickened blueberry mixture over all. Cover pan with lid or plastic wrap. Place in refrigerator overnight or for at least four hours to allow dessert to become set.
Using a sharp knife, cut dessert into 24 squares and serve immediately while cold. ENJOY this decadent dessert!!!