Making a Blueberry Crumble Cheesecake involves a few key steps. Follow the instructions closely for the best results:

1. Preheat the Oven: Preheat your oven to 325°F (160°C).

2. Prepare the Crust: If you prefer a cookie crust, crush graham crackers or digestive biscuits and mix them with melted butter. Press the mixture into the bottom of a springform pan to form the crust and set it aside.

3. Make the Blueberry Filling: In a saucepan, combine the blueberries, sugar, lemon juice, and cornstarch. Cook over medium heat for about 5-7 minutes until the blueberries start to burst.

4. Prepare the Cheesecake Mixture: In a large mixing bowl, beat the cream cheese with granulated sugar until smooth. Add in the vanilla extract and mix well.

5. Add the Eggs: Incorporate the eggs one at a time, mixing well after each addition. Then, fold in the sour cream until fully integrated.

6. Layer the Blueberry Filling: Pour half of the cheesecake mixture over the prepared crust. Then gently spoon the blueberry filling over this layer. Pour the remaining cheesecake mixture on top.

7. Make the Crumble: In a separate bowl, mix flour, oats, brown sugar, melted butter, cinnamon, and salt until crumbly. Sprinkle it evenly over the cheesecake.

8. Bake the Cheesecake: Place the cheesecake in the preheated oven and bake for about 1 hour or until the edges are set, and the center is slightly jiggly.

9. Cool the Cheesecake: Turn off the oven and let the cheesecake cool in the oven with the door ajar for 1 hour. Then, transfer it to the fridge and chill for at least 4 hours or overnight for best results.

10. Serve: Carefully remove the cheesecake from the springform pan and slice it to serve.