Preheat your oven to 160°C (325°F) and prepare your springform pan by lining the bottom with parchment paper.

In a food processor, combine digestive biscuits and 2 tablespoons of granulated sugar. Add melted butter and blend until resembling wet sand. Press into prepared springform pan and bake for 10 minutes. Let cool.

In a medium bowl, toss blueberries with 1 tablespoon of granulated sugar, 1 tablespoon of flour, and lemon juice. Set aside.

Mix together 110 g of flour and 80 g of dark brown sugar in a separate bowl. Pour in melted butter and mix until crumbly. Set aside.

In a mixer, beat the cream cheese for 1 minute until smooth. Gradually add 260 g of granulated sugar and mix until creamy.

In another bowl, whisk sour cream and cornstarch until smooth. Add to cream cheese mixture with vanilla extract and mix until combined.

Add eggs two at a time, mixing on low speed until incorporated. Be careful not to overmix.

Pour the cheesecake batter into the crust. Scatter blueberry mixture on top and sprinkle crumble topping over the blueberries.

Place the springform pan inside a larger pan and fill with boiling water about halfway up the sides of the springform pan. Alternatively, wrap the springform pan tightly with foil and place directly into the water bath.

Bake for 1 hour 20-30 minutes until edges set and center slightly jiggles. Turn off the oven, crack the door, and let cool for 1 hour.

After an hour, remove cheesecake from the water bath, cool at room temperature for 1 hour, then refrigerate for at least 6 hours, preferably overnight before serving.