Preheat oven to 325 degrees.
Line a 9×13 pan {or a quarters baking sheet} with foil and spray foil with cooking spray.
In a large bowl, stir together the flour, brown sugar, and salt.
Cut in 1/2 cup butter until mixture resembles coarse crumbs. {I just use a fork.}
Press into prepared pan and bake for 20 minutes in the preheated oven.
While the crust is baking, prepare the filling.
In a large bowl stir together the eggs, corn syrup, white sugar, butter, and vanilla just until combined. Stir in the chopped pecans.
Spread the filling evenly over the crust as soon as it comes out of the oven.
Bake for 20- 25 minutes in the preheated oven, or until set. Allow to cool completely on a wire rack before slicing into bars.