In a large bowl, cream together the softened brown butter, brown sugar, vanilla, and salt until combined. Then mix in the flour until the dough comes together into a ball.
Line a 9x9 inch square cake pan with parchment paper. To make a parchment sling, cut the parchment paper slightly smaller than the width of the cake pan and make sure it fits flatly in the bottom. Then lightly spray the bottom and sides of the pan with a vegetable oil based spray (I love Bakers Joy or Everbake). Place you parchment paper sling in the bottom of the pan and smooth it out so that it sticks to the pan spray (you can use metal binder clips to secure it to the pan). After baking you’ll be able to just slide the pecan pie bars right out of the pan!
Press the dough into your lined baking pan and smooth into an even layer. Poke a few holes in the dough with a fork to allow air to escape while baking.
Let the cookie crust chill in the fridge for about 20 minutes to firm up before baking.
While the crust is chilling preheat the oven to 350°F.
Bake the crust at 350°F for 15 minutes or until the top is lightly browned.
Remove from the oven and let cool slightly while you make the filling.
Pecan Pie Filling
In a medium bowl, whisk together the corn syrup, eggs, melted butter, brown sugar, vanilla, cinnamon, and salt until combined and smooth.
Add the chopped toasted pecans to the slightly cooled cookie crust.
Pour the filling evenly over the pecans.
If desired, add the whole pecan halves on top and arrange into a pattern.
Bake at 350°F for 45-60 minutes or until the filling is set. It should jiggle just slightly when jostled. If the top of the cookie bars are getting too dark during baking, you can loosely tent the pie with aluminum foil for the remainder of the baking time.
Remove from the oven and allow the bars to cool completely to room temperature (at least 4 hours) in the baking pan before slicing. Top with flaky sea salt if desired.
Once cool, use the parchment paper sling to pull the pecan cookies out of the pan and then slice into bars.
You can also cut the pecan pie cookie bars into smaller squares if desired!
Notes
Store covered in the fridge for up to 4 days. I like to remove them from the fridge for an hour before serving.To make brown butter, melt unsalted butter over medium heat, stirring frequently. Watch closely for the butter to develop brown specs and a nutty aroma. Once you start seeing brown specs, let cook for just a few seconds longer (watch very carefully or it will burn). Remove from the heat and pour into a small bowl so that it doesn't continue to cook. Set aside and let cool for at least 20 minutes in the fridge until solid but pliable. Note: For every ½ cup (1 stick or 113g), you'll lose about 1 tablespoon (14g) to evaporation while cooking. So you can either add in an extra 1 tablespoon before browning, or if you're browning big batches, just make up the weight difference in your recipe with regular unsalted butter if needed.