Preheat your oven to 325 F and grease and line a 9 x 13 baking dish with foil.
In a bowl, set aside 2/3 cup of the dry cake mix.
In a medium bowl, mix remaining cake mix with 1 egg and melted butter until a dough forms.
Spread the batter in the baking dish and bake for 15 minutes.
In the bowl with the 2/3 cup cake mix, whisk in the corn syrup, 3 eggs, dark brown sugar, salt, and vanilla until smooth.
Fold in the chocolate chips and chopped pecans.
Once the bars have baked for 15 minutes, pour the pecan topping evenly on top and finish baking for 35-40 minutes or until center is set.
Let cool completely before cutting into the bars.
Top with ganache and extra nuts.