Preheat your oven to 325°F (160°C) and prepare an 8×8-inch baking dish with grease or parchment paper. In a medium bowl, mix the graham cracker crumbs, granulated sugar, and melted butter until well blended. Press the mixture firmly into the base of the dish to form a crust. Bake for 10 minutes, then let it cool slightly.

Beat the softened cream cheese in a large mixing bowl until smooth and creamy. Gradually add in the granulated sugar, mixing until well combined. Add each egg one at a time, mixing well after each addition. Stir in the vanilla extract, sour cream, and lemon juice until smooth.

Pour the cheesecake filling over the cooled crust, spreading it evenly. Bake for 25–30 minutes or until the edges are set, and the center remains slightly jiggly. Let it cool at room temperature.

Combine the blueberries, granulated sugar, cornstarch, and lemon juice in a small saucepan over medium heat. Cook for about 5–7 minutes, stirring gently until the blueberries begin to burst and the mixture thickens. Remove from heat and let it cool slightly.

Spread the blueberry topping evenly over the cooled cheesecake layer. Refrigerate the bars for at least 4 hours until fully chilled and set.

Slice into squares and serve chilled, enjoying the summer goodness!