I started by preheating my oven to 325°F (160°C). Then, I mixed the graham cracker crumbs, sugar, and melted butter until everything was coated. After pressing it firmly into the bottom of my springform pan, I baked it for about 8 minutes, just enough to set. I let it cool while working on the filling.
In a large mixing bowl, I beat the softened cream cheese with sugar until smooth and creamy. Next, I added the eggs one at a time, mixing just until combined. I gently stirred in the sour cream and vanilla extract. The batter turned out velvety and rich, and I poured it over the cooled crust.
To keep the cheesecake from drying out, I wrapped the bottom of my springform pan in foil and placed it in a water bath. It baked for about 50 minutes until the edges were firm but the center was still a little wobbly. After turning off the oven, I let it sit with the door cracked open for an hour—this prevents cracks.
While the cheesecake cooled, I cooked blueberries, sugar, cornstarch-water mixture, and lemon juice in a saucepan. Stirring constantly, the mixture thickened into a shiny, sweet-tart sauce in about 6 minutes. I let it cool completely before using it.
Finally, I spread the blueberry topping over the cooled cheesecake and refrigerated it for at least 6 hours. Overnight chilling gave me the best results. When ready, I released it from the springform pan, sliced it, and served it chilled.