1. Preheat oven to 325°F (160°C). Line a 9-inch springform pan with parchment paper.

2. Pulse graham crackers and sugar in food processor or crush in zip bag. Mix with melted butter until sandy.

3. Press mixture firmly into pan base and 1 inch up the sides. Bake for 10 minutes. Let cool. Leave oven on.

4. Toss blueberries with sugar, flour, and lemon juice. Set aside.

5. For crumble: Mix flour and brown sugar. Add melted butter and mix with fork until crumbly.

6. Beat cream cheese until smooth. Add sugar; mix 1 minute. Whisk sour cream and cornstarch in small bowl; add with vanilla. Mix on low.

7. Add eggs two at a time, mixing on low until just combined.

8. Pour batter into crust. Scatter blueberries evenly on top. Sprinkle with crumble.

9. Place springform inside a cake pan, then place both in a roasting pan. Add hot water halfway up the outer pan.

10. Bake 1 hour 25 minutes, until center jiggles slightly.

11. Turn off oven, crack door, and let cheesecake cool inside for 1 hour.

12. Cool on counter for another hour, then refrigerate for 6+ hours or overnight.

13. Slice and serve with optional lemon zest, blueberry sauce, or whipped cream.