Prepare for Baking:

1. Position your oven rack in the lower third of the oven. Preheat the oven to 350°F (175°C).
2. Wrap the outside bottom and sides of a 9-inch springform pan tightly with heavy-duty aluminum foil. This prevents water from seeping in during the water bath. Make sure it’s wrapped securely with no gaps.
3. Grease the inside of the springform pan lightly with butter or non-stick spray.

Make the Crust:

4. In a medium bowl, combine graham cracker crumbs, sugar, and a pinch of salt. Pour in the melted butter and stir with a fork until the mixture resembles wet sand and holds together when pressed.
5. Pour the crumb mixture into the prepared springform pan. Using the bottom of a measuring cup or glass, press the crumbs firmly and evenly into the bottom of the pan. Press some crumbs slightly up the sides (about ½ inch) to create a small edge.
6. Bake the crust for 10 minutes. Remove from oven and set aside to cool while you make the filling. Keep the oven on.

Make the Cream Cheese Filling:

7. In a large bowl or stand mixer fitted with the paddle attachment, beat the softened cream cheese on medium speed for 2-3 minutes until completely smooth and creamy with no lumps. Scrape down the sides and bottom of the bowl frequently.
8. Add the sugar and beat on medium speed for another 2 minutes until well combined and fluffy.
9. Add the sour cream and vanilla extract. Beat on low speed until fully incorporated, about 1 minute.
10. Add the eggs one at a time, beating on low speed after each addition just until combined. Do not overmix—this incorporates too much air and can cause cracks. Scrape down the bowl after each egg.
11. If using flour, sift it over the batter and gently fold it in with a spatula just until no streaks remain.
12. Pour the filling over the baked crust in the springform pan. Gently tap the pan on the counter a few times to release any air bubbles. Use a spatula to smooth the top.

Bake the Cheesecake (Water Bath Method):

13. Place the foil-wrapped springform pan inside a large roasting pan. Carefully pour hot water into the roasting pan until it reaches halfway up the sides of the springform pan (about 1-1½ inches of water).
14. Carefully transfer the roasting pan with both pans to the oven. Bake at 350°F for 55-70 minutes. The cheesecake is done when the edges are set but the center still jiggles slightly (about a 2-inch circle in the middle). It should not look liquid, just slightly wobbly.
15. Turn off the oven and crack the oven door open about 1 inch. Let the cheesecake cool in the oven for 1 hour. This gradual cooling helps prevent cracks.
16. After 1 hour, remove the cheesecake from the water bath and remove the foil. Place the springform pan on a wire rack and let cool to room temperature, about 2 hours.
17. Once at room temperature, cover the top of the pan loosely with plastic wrap or foil (don’t let it touch the surface). Refrigerate for at least 4 hours, preferably overnight. Cheesecake must be completely cold before adding topping or serving.

Make the Blueberry Topping:

18. In a medium saucepan, combine the blueberries, sugar, lemon juice, water, and a pinch of salt. Bring to a boil over medium-high heat, stirring occasionally.
19. In a small bowl, whisk together the cornstarch with 1 tablespoon of water to create a slurry (smooth paste).
20. Once the blueberry mixture is boiling and the berries start to burst (about 3-4 minutes), stir in the cornstarch slurry. Continue cooking, stirring constantly, for 1-2 minutes until the mixture thickens to a glossy, jam-like consistency.
21. Remove from heat and let the blueberry topping cool to room temperature. It will thicken more as it cools. You can make this up to 3 days ahead and refrigerate.

Assemble and Serve:

22. Once the cheesecake is completely chilled (at least 4 hours), run a thin knife around the edge of the pan to loosen the cheesecake. Release and remove the springform ring.
23. Spoon the cooled blueberry topping over the top of the cheesecake, spreading it evenly and letting some drip down the sides for a beautiful presentation.
24. Slice with a sharp knife, wiping the blade clean between each cut for neat slices.
25. Serve chilled and enjoy!