In a medium saucepan, combine 2 cups of blueberries, ¼ cup of sugar, 1 tablespoon of cornstarch, 2 tablespoons of lemon juice, and ½ cup of water. Cook over medium heat for 5-10 minutes until it thickens to a syrupy consistency. Let cool before refrigerating.

In a mixing bowl, combine 1 ½ cups of graham cracker crumbs, ½ cup of melted unsalted butter, and ¼ cup of granulated sugar. Press firmly into the bottom of a 9-inch springform pan and chill for about 10 minutes.

Using an electric mixer, beat 16 ounces of softened cream cheese until fluffy. Gradually add 1 ½ cups of Cool Whip, ½ cup of icing sugar, 1 teaspoon of vanilla extract, and 2 tablespoons of lemon juice. Mix until smooth and spread over the chilled crust.

Spoon the cooled blueberry topping over the cream cheese layer, cover with plastic wrap, and chill in the refrigerator for 3-4 hours until set.