1. Prepare the crust:
Preheat the oven to 160°C (325°F). In a medium bowl, combine the crushed biscuits or graham crackers, sugar, and melted butter. Mix until the crumbs are fully coated with the butter.

Press the mixture into the bottom of a greased 9-inch springform pan, making sure it’s evenly distributed and compacted. Bake the crust in the preheated oven for about 10 minutes. Afterward, remove from the oven and allow it to cool while you prepare the filling.

2. Prepare the cheesecake filling:
In a large mixing bowl, beat the cream cheese with a hand mixer or stand mixer until smooth and creamy. Add the sugar and vanilla extract, and beat until well combined.

Add the eggs, one at a time, beating well after each addition. Add the sour cream and heavy cream, and continue mixing until everything is smooth and well incorporated.

3. Assemble the cheesecake:
Pour the cheesecake filling into the cooled crust, smoothing the top with a spatula. Place the cheesecake in the oven and bake for about 55–60 minutes, or until the center is set but slightly jiggly when you tap the pan.

Turn off the oven and let the cheesecake cool in the oven with the door slightly open for about 1 hour. Afterward, remove the cheesecake and let it cool completely at room temperature. Then, chill the cheesecake in the refrigerator for at least 4 hours, or preferably overnight, to fully set.

4. Make the blueberry topping:
In a small saucepan, combine the blueberries, sugar, and lemon juice. Cook over medium heat until the berries begin to release their juices, about 5 minutes.

In a separate small bowl, mix the cornstarch with water to form a slurry. Add this to the blueberry mixture and stir well. Continue cooking for 2–3 minutes, or until the sauce thickens. Remove from heat and let it cool to room temperature.

5. Assemble the cheesecake and topping:
Once the cheesecake has fully chilled, remove it from the springform pan and place it on a serving platter. Pour the cooled blueberry topping over the cheesecake, spreading it evenly.

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