Preheat the oven to 350 degrees.
Line a 9X9 inch pan with parchment paper.
Prepare the brownie mix as directed on the box. Stir until just mixed - do not use an electric mixer.
Pour this batter into the prepared pan.
Bake the brownies for half of the recommended baking time plus 5 more minutes- to start. (For example, if the box says they need 40 minutes to bake, you will bake them for 25 minutes before adding the pecan pie topping.)
While the brownies are baking, you will prepare the pecan pie topping.
In a medium bowl, whisk together the melted butter, corn syrup, brown sugar, vanilla, and salt. Then mix in the eggs. When that is very well mixed, stir in the chopped pecans.
When the brownies are finished their first baking time, take them out of the oven and spread the pecan mixture evenly over them. (If the brownies still look wet, they need more time. The top should be just set when you take them out of the oven.)
Place the brownies (with the pecan pie topping added) back into the oven and continue baking for another 25-30 minutes. The top should be just set - not jiggly. The pie topping will continue to set as it cools.
Allow the brownies to cool completely on a cooling rack. You will be able to slice them more neatly if you chill them in the refrigerator for at least 2 hours before cutting.