1. Make the Crust

• Preheat your oven to 325°F (160°C).
• In a bowl, mix the biscuit crumbs, granulated sugar, and melted butter until fully combined.
• Press the mixture firmly into the bottom of a 9-inch springform pan to form an even crust layer.
• Bake the crust for 10 minutes, then set aside to cool while you prepare the filling.

2. Prepare the Blueberry Swirl

• In a small saucepan, combine blueberries, sugar, and lemon juice. Cook over medium heat, stirring occasionally, until the berries break down and release their juices.
• Stir in the cornstarch slurry and continue cooking for 2–3 minutes, until thickened.
• Remove from heat and allow the mixture to cool. Use a blender or immersion blender to puree if a smoother swirl is desired.

3. Make the Cheesecake Filling

• In a large mixing bowl, beat the softened cream cheese until smooth and creamy.
• Add the sugar and vanilla extract and beat until fully combined and fluffy.
• Add eggs one at a time, mixing on low speed and scraping the sides of the bowl between additions.
• Mix in sour cream and heavy cream just until incorporated. Do not overmix.

4. Assemble the Cheesecake

• Pour the cheesecake batter over the cooled crust and smooth the top with a spatula.
• Drop spoonfuls of the blueberry sauce on top of the filling.
• Use a skewer or knife to gently swirl the blueberry mixture into the cheesecake in a figure-eight motion, creating marbled patterns.

5. Bake the Cheesecake

• Place the springform pan into a larger roasting pan and pour hot water into the roasting pan to create a water bath (optional but helps prevent cracking).
• Bake at 325°F (160°C) for 60–70 minutes, until the edges are set and the center is slightly jiggly.
• Turn off the oven and leave the cheesecake inside with the door slightly open for 1 hour.

6. Chill and Serve

• Remove the cheesecake from the oven and water bath. Let it cool completely at room temperature.
• Refrigerate for at least 6 hours or overnight before slicing.
• Slice with a hot knife for clean edges, wiping the blade between cuts.