Preheat the oven to 350°F (175°C) and grease a 9×13-inch (23x33 cm) baking dish with butter or nonstick spray. Set it aside.
In a large bowl, use an electric mixer to beat the flour, sugar, salt, chilled butter, and vanilla until the mixture becomes crumbly.
Set aside 1 cup of the crumbly mixture. Press the remaining mixture firmly into the prepared baking dish. Bake for 15 minutes.
While the crust is baking, prepare the filling. In another clean and large bowl, beat the eggs with an electric mixer until frothy.
Add the sugar, sour cream, flour, and salt to the bowl, and mix until thoroughly combined. Gently stir in the fresh blueberries.
Spoon the filling evenly over the baked crust.
Top the filling with the reserved 1 cup of the crumbly mixture. Bake for 45-55 minutes or until the top turns golden brown.
Allow the bars to cool for 1 hour before slicing and serving. Enjoy the delectable Blueberry Pie Bars!