- Preheat your oven to 350°F (175°C). Grease an 8x8-inch baking dish or line it with parchment paper for easy removal. 
- In a medium bowl, combine the blueberries, lemon juice, granulated sugar, and cornstarch. Gently toss to coat the blueberries and set aside. 
- In another bowl, mix together the flour, rolled oats, brown sugar, cinnamon, and salt. Pour in the melted butter and stir until the mixture is crumbly. 
- Press half of the oat mixture into the bottom of the prepared baking dish to form a crust. Bake for 10 minutes, then remove from the oven. 
- While the crust is baking, prepare the cheesecake layer. In a mixing bowl, beat the softened cream cheese, powdered sugar, vanilla extract, and egg until smooth and creamy. 
- Spread the cheesecake mixture evenly over the baked crust. Spoon the blueberry mixture over the cheesecake layer, distributing it evenly. Finally, sprinkle the remaining oat mixture on top. 
- Return the dish to the oven and bake for an additional 25-30 minutes, or until the topping is golden brown and the cheesecake is set. Allow to cool completely in the pan before slicing into bars. 
- Serve chilled or at room temperature. For best results, refrigerate for at least 2 hours before serving.