Preheat oven to 350 degrees and line a 9x13 baking pan with parchment paper
Using a standing mixer, beat together the butter, eggs, brown sugar, sugar, salt, and vanilla until combined and smooth
Gradually beat in the flour and mashed banana until combined
Fold in 2 C of chocolate chips
Pour the batter into the baking dish
Sprinkle the remaining chocolate chips onto the top of the brownies
Bake in the oven for 30-40 minutes or until a toothpick comes out of the center clean
Allow to cool before cutting into bars
Enjoy!