Preheat the oven to 325°F. Spray the sides and bottom of a 9-inch springform pan with cooking spray and line with parchment paper.

In a medium bowl, mix graham cracker crumbs, sugar, and melted butter with a fork until all crumbs are moistened.

Press the crumb mixture into the bottom and up the sides of the prepared pan using the bottom of a glass or measuring cup.

Bake for 10 minutes, then remove from the oven and lower the temperature to 300°F. Let the crust cool.

Wrap a large piece of aluminum foil around the outside of the pan to prevent water from leaking in during the water bath. Alternatively, place the pan in a slightly larger pot for protection.

Using a stand mixer with a paddle attachment or a handheld mixer, beat the cream cheese on low speed until smooth.

Add sugar and cornstarch, continuing to beat on low until well combined and smooth.

Scrape down the bowl and add sour cream, lemon zest, and lemon juice, beating until smooth.

Add eggs and yolk one at a time, beating slowly just until combined. Do not overbeat. Scrape the bowl to ensure everything is fully mixed. Fold in the blueberries.

Pour the batter into the prepared crust and place the pan into a larger pan. Pour a few cups of boiling water into the larger pan, about a few inches up the sides, avoiding going over the top.

Bake at 300°F for 1 hour and 20 minutes to 1 hour and 30 minutes. The cheesecake is ready when the edges are set, and the center slightly jiggles.

Turn off the oven and let the cheesecake cool for 30 minutes inside. Then, crack the door open and cool for another 30 minutes.

Remove the cheesecake from the water bath and foil. Run a knife around the edge to loosen it and cool completely on a rack.

Cover loosely with plastic wrap and refrigerate for at least 8 hours or overnight until firm and chilled.

For the topping, combine fresh blueberries, sugar, water, and lemon juice in a saucepan. Bring to a boil over high heat.

Reduce heat and let blueberries burst, stirring occasionally for 4-5 minutes.

Mix cornstarch with cold water to make a slurry, then stir it into the blueberry sauce, cooking on high while whisking constantly until thickened, about 1 minute.

Cool the sauce in a separate bowl, then refrigerate until ready to use.

Remove the cheesecake from the fridge and springform pan. Pour the cooled blueberry sauce on top. Garnish with a lemon twist. Enjoy!