01 -
Preheat oven to 160°C conventional. Line the base of a 23 cm springform tin with parchment paper and set aside.
02 -
In a food processor, pulse digestive or graham crackers with granulated sugar to fine crumbs. Add melted butter and blend until the mixture resembles damp sand.
03 -
Press the crumb mixture firmly into the base and up the sides of the prepared tin using the bottom of a glass. Bake for 10 minutes, then cool until just warm. Keep oven on.
04 -
In a small bowl, combine blueberries, granulated sugar, all-purpose flour, and lemon juice. Mix until the berries are evenly coated and no dry flour remains; set aside.
05 -
In another bowl, mix flour and dark brown sugar. Pour in melted butter and mix with a fork until large, moist crumbs form and there is no dry flour left. Set aside.
06 -
In a stand mixer with paddle attachment or mixing bowl with electric hand mixer, cream cream cheese on low speed for 1 minute. Add granulated sugar and mix on low for another minute, scraping down the sides as needed. Continue mixing for 30 seconds until smooth.
07 -
In a separate bowl, whisk sour cream and cornstarch until smooth. Add this mixture and vanilla extract to the cream cheese mixture. Mix on low speed until well combined.
08 -
Add eggs two at a time, mixing on low speed after each addition until fully integrated. Scrape the bowl and give a final gentle mix to ensure all ingredients are incorporated.
09 -
Pour cheesecake batter onto the cooled cookie crust. Evenly scatter blueberry mixture over the cheesecake, followed by sprinkling the crumble topping.
10 -
Place the springform tin inside a 30 cm cake pan. Set this onto a larger roasting pan and surround with boiling water to reach halfway up the cake pan sides, ensuring the cheesecake is protected from direct water contact. Alternatively, wrap the springform with triple-layered aluminium foil before placing in the water bath.
11 -
Bake in the preheated oven for 1 hour 20 to 1 hour 30 minutes. The center should still be slightly wobbly when gently shaken.
12 -
Turn off the oven. Leave the cheesecake inside with the oven door slightly ajar for 1 hour to cool slowly and prevent cracking.
13 -
Remove the cheesecake from the water bath and transfer to a wire rack. Allow to cool to room temperature for about 1 hour. Once fully cooled, refrigerate for at least 6 hours, preferably overnight, before serving.