Prepare the crust: In a medium-sized bowl, combine the graham cracker crumbs, sugar, and melted butter. Stir until the crumbs are evenly coated. Press the mixture firmly into the bottom of a 9-inch springform pan or pie dish to form a crust. Place in the fridge to chill while preparing the filling.

Make the cheesecake filling: In a large bowl, beat the heavy cream with an electric mixer until soft peaks form. In another bowl, beat the softened cream cheese until smooth. Add the powdered sugar, vanilla extract, and lemon juice, and continue to beat until fully combined and creamy.

Combine the filling and whipped cream: Gently fold the whipped cream into the cream cheese mixture until smooth and well combined. Be careful not to deflate the whipped cream. Once mixed, pour the filling over the chilled graham cracker crust and spread evenly. Place in the fridge to set for at least 4 hours, or overnight for best results.

Prepare the blueberry topping: In a medium saucepan, combine the blueberries, sugar, and lemon juice over medium heat. Stir occasionally until the berries start to release their juices, about 5-7 minutes. If you prefer a thicker topping, mix the cornstarch with a little water to form a slurry, then add it to the saucepan. Stir until the mixture thickens, about 2-3 minutes. Remove from heat and let it cool completely.

Assemble the cheesecake: Once the cheesecake filling has set, spoon the cooled blueberry topping over the cheesecake. Spread it evenly across the surface.

Serve: Slice and serve immediately or store in the fridge for up to 2-3 days. Garnish with extra fresh blueberries, if desired.