1. Preheat oven to 325°F (163°C).
2. Prepare the graham cracker crust by mixing crushed graham crackers with melted butter and sugar.
3. Press the crust mixture firmly into the bottom and slightly up the sides of a springform pan.
4. Bake the crust for about 10 minutes, then let it cool while preparing the filling.
5. In a large mixing bowl, beat room-temperature cream cheese until smooth.
6. Add sugar, sour cream, vanilla extract, and lemon zest, then mix until combined.
7. Add eggs one at a time, mixing gently after each addition to avoid overbeating.
8. Pour the cheesecake filling over the cooled crust, smoothing the top.
9. Prepare the blueberry sauce by cooking blueberries with sugar, lemon juice, and cornstarch until thickened.
10. Swirl some of the blueberry sauce into the cheesecake filling for a marbled effect if desired.
11. Bake the cheesecake for 45-60 minutes until the edges are set but the center is slightly jiggly.
12. Turn off the oven and let the cheesecake cool inside with the door slightly open to prevent cracks.
13. Once cooled to room temperature, refrigerate for at least 4-6 hours or overnight.
14. Before serving, spread the remaining blueberry sauce evenly over the top of the cheesecake.
15. Slice, serve, and enjoy your homemade blueberry cheesecake.
16. Store leftovers in the refrigerator for up to 5 days or freeze for up to 2 months if wrapped well.