Preheat your oven to 350°F (175°C). Grease a 9x9 inch baking pan and line it with parchment paper, leaving some overhang on the sides for easy removal later.
In a medium bowl, combine the graham cracker crumbs and melted butter. Mix until the crumbs are evenly coated. Press this mixture firmly into the bottom of the prepared baking pan to form a crust. Bake for 8-10 minutes, and then let it cool.
In a large mixing bowl, beat the cream cheese and granulated sugar together until smooth and creamy, about 2-3 minutes.
Add the eggs one at a time, beating well after each addition. Then, mix in the vanilla extract, lemon zest, and lemon juice until fully combined.
In a small bowl, toss the fresh blueberries with cornstarch until they’re well coated. Gently fold the blueberries into the cheesecake mixture.
Pour the cheesecake filling over the cooled crust, spreading it evenly.
Bake in the preheated oven for 30-35 minutes or until the edges are set and the center is slightly jiggly.
Once baked, allow the cheesecake bars to cool to room temperature, and then refrigerate for at least 4 hours, ideally overnight for a perfect texture.
Once chilled, lift the bars out of the pan using the parchment paper overhang. Cut into squares or rectangles.
Serve topped with additional fresh blueberries and a dusting of powdered sugar if desired.