Preheat oven to 160°C (325°F). Line the bottom of a 9-inch (23 cm) springform pan with parchment paper.

Make the Crust
2. Blend the biscuits and sugar in a food processor until fine crumbs form.
3. Add melted butter and mix until combined.
4. Press mixture firmly into the bottom and slightly up the sides of the pan.
5. Bake for 10 minutes, then let cool while keeping the oven on.

Prepare Blueberries and Crumble
6. In a bowl, mix blueberries, sugar, flour, and lemon juice until coated. Set aside.
7. In another bowl, combine flour and brown sugar. Add melted butter and mix with a fork until crumbly. Set aside.

Make the Cheesecake Filling
8. Beat cream cheese on low speed until smooth (about 1 minute).
9. Add sugar and mix for another minute. Scrape the bowl.
10. Mix sour cream with cornstarch, then add along with vanilla extract. Mix until combined.
11. Add eggs two at a time, mixing on low speed until just incorporated. Do not overmix.

Assemble and Bake
12. Pour cheesecake batter into the prepared crust.
13. Spoon blueberries evenly over the top, followed by the crumble.
14. Place the springform pan inside a larger pan and set into a water bath (or wrap tightly with foil).
15. Bake for 1 hour 20–30 minutes, until edges are set and center slightly wobbly.

Cool and Set
16. Turn off oven, crack the door open, and let cheesecake cool inside for 1 hour.
17. Remove from oven and water bath, then cool to room temperature.
18. Refrigerate for at least 6 hours or overnight before serving.