Preheat your oven to 325°F. Wrap heavy-duty aluminum foil around the bottom and sides of a 9-inch springform pan; then, spray the inside with nonstick spray.
For the crust, mix graham cracker crumbs, melted butter, and sugar together. Press the mixture into the bottom and up the sides of the pan. Bake for 10-12 minutes until golden, and let it cool completely.
Lower the oven temperature to 300°F.
In a large bowl, beat the cream cheese until smooth. Add sugar, salt, and flour, mixing until there are no lumps.
Add the sour cream, lemon zest, lemon juice, and vanilla; beat until everything is smooth.
Add the eggs one at a time, mixing just until combined, scraping down the sides as needed.
To the batter, fold in blueberries that you have tossed with the remaining 1 teaspoon of flour.
Pour the batter over the crust. Place the pan into a large roasting pan and fill it with hot water halfway up the sides of the springform pan.
Bake for 1 hour and 20-25 minutes, until the center is set but still has a slight jiggle.
Turn off the oven, crack the door, and let the cheesecake sit inside for 30-45 minutes to continue cooking.
Remove from the oven and water bath, discard the foil, and transfer it to a wire rack. Allow it to cool to room temperature, then refrigerate for at least 8 hours.
For the topping, in a small saucepan, combine 2 cups of blueberries, lemon juice, and vanilla. Bring to a boil and simmer for 7 minutes until the blueberries break down. Stir in sugar and cornstarch dissolved in water, continuing to simmer until thickened. Remove from heat and stir in the remaining blueberries. Let it cool.
Drizzle the sauce over the chilled cheesecake before serving. For a swirl variation, drop spoonfuls of the cooled blueberry mixture onto the batter before baking and swirl with a knife.
Notes
Chill the cheesecake fully for the best texture and taste. Use room temperature ingredients for a smoother batter.