Preheat oven to 350°F (175°C).
In a bowl, mix flour, butter, and 2 tbsp sugar until crumbly.
Press evenly into the bottom of a greased 9x9-inch baking pan.
Bake for 15–18 minutes, until lightly golden. Let cool completely.
Beat cream cheese, 1/2 cup sugar, and vanilla until smooth and fluffy.
Gently fold in whipped cream (or whipped topping) until well combined.
Spread this mixture evenly over the cooled crust. Chill in refrigerator while you prepare topping.
In a saucepan, combine sugar, cornstarch, and water. Stir until smooth.
Add blueberries and cook over medium heat, stirring constantly until thickened and bubbly (about 5–7 minutes).
Stir in lemon juice and let cool completely.
Spread the cooled blueberry topping evenly over the cream layer.
Chill for at least 2 hours (best overnight) before serving.