01 - Preheat oven to 320°F. Line the bottom of a 9-inch springform pan with parchment paper. In a bowl, mix graham cracker crumbs, melted butter, sugar, and salt. Press mixture firmly into the pan base. Bake for 10 minutes; cool slightly.
02 - Beat cream cheese until smooth. Add sugar, vanilla, and lemon juice; mix well. Add eggs one at a time, beating after each. Fold in sour cream and flour until just combined.
03 - Pour filling over the cooled crust. Tap pan gently to release air bubbles. Bake for 50-60 minutes, until edges are set but center is slightly wobbly. Turn off oven, crack door, and let cheesecake cool inside for 1 hour.
04 - In a saucepan, combine blueberries, sugar, water, and lemon juice. Cook over medium heat until berries soften and release juices. Stir in cornstarch slurry; simmer until thickened (2–3 minutes). Cool.
05 - Refrigerate cheesecake for at least 4 hours (preferably overnight). Spread blueberry topping over chilled cheesecake before serving.