Preheat the oven to 160ºC/325ºF.

Prepare a 23 cm/9 inch springform tin with parchment paper.

In a food processor, blend the digestive or graham crackers with 2 tbsp of granulated sugar until sandy. Add melted 75 g butter and blend.

Press the mixture into the bottom and sides of the springform pan and bake for 10 minutes. Allow to cool.

Prepare blueberries by mixing with 1 tbsp granulated sugar, 1 tbsp flour, and lemon juice.

To make the crumble, mix 110 g flour with 80 g dark brown sugar and melted 70 g butter until crumbly.

In a mixing bowl, beat the cream cheese for a minute, add 260 g granulated sugar and mix.

In another bowl, mix together 200 g sour cream and 1.5 tbsp cornstarch, then add to cream cheese and blend.

Add eggs one at a time, incorporating well after each addition.

Pour the cheesecake mixture on top of the crust, then add blueberries and crumble on top.

Bake in a water bath for 80-90 minutes or until set.

Cool in the oven for an hour, then refrigerate for at least 6 hours or overnight before serving.