Creating Blueberry Cream Cheese Bars is straightforward if you follow these steps:

1. Preheat Oven: Begin by preheating your oven to 350°F (175°C) and greasing a 9×9-inch baking pan.

2. Make the Crust:
1. In a medium bowl, combine flour, sugar, butter, egg yolk, and salt.
2. Mix until crumbly and well combined.
3. Press the mixture evenly into the bottom of the prepared baking pan.

3. Prepare the Cream Cheese Layer:
1. In a separate bowl, beat the softened cream cheese until smooth.
2. Add granulated sugar, egg, and vanilla extract; mix until fully combined.
3. Spread the cream cheese mixture evenly over the crust in the baking pan.

4. Make the Blueberry Topping:
1. In a medium bowl, combine blueberries, granulated sugar, cornstarch, and lemon juice.
2. Gently toss the blueberries until they are well coated.

5. Assemble the Bars:
1. Distribute the blueberry mixture evenly on top of the cream cheese layer.
2. Use a spatula to gently press the blueberries into the cream cheese layer for even distribution.

6. Bake: Place the baking pan in the preheated oven. Bake for 30-35 minutes, or until the cream cheese layer is set and slightly golden.

7. Cool: Remove the pan from the oven and allow it to cool at room temperature for about 15-20 minutes.

8. Refrigerate: For the best flavor, refrigerate the bars for at least 1 hour before slicing them into squares.

9. Slice and Serve: Cut the cooled bars into squares and enjoy!