Preheat the oven to 350 degrees. Prepare an 8 by 8 pan with parchment paper or spray with non-stick spray.
In a small bowl, mix together the base ingredients (melt the butter in the microwave): melted butter, brown sugar, flour and salt. Press into an even layer at the bottom of the pan.
Using the same bowl (or a different one if you really want to wash two bowls) add the filling ingredients: melted butter, brown sugar, flour, salt, vanilla and two eggs. Mix together with a fork or spoon until fully incorporated.
Pulse pecans in a blender or food processor a few times to chop into small pieces.
Add chocolate chips and pecans to the filling and mix together. Add a splash of bourbon if desired.
Spread the filling mixture on top of the base bar layer.
Bake for 40-45 minutes until edges are brown and the filling mixture is set. See recipe notes about length of baking time needed.
Allow the bars to cool completely before cutting and serving. Enjoy!