INSTRUCTIONS: 

1. Preheat the oven to 350 F. Line an 8×8 square baking tin with parchment paper, spray with non-stick spray or grease with butter and set aside. 
2. For the brownie batter: In a medium bowl whisk together eggs, sugars, butter and vanilla extract until just combined. Whisk together flour, cocoa powder, baking powder and salt in a separate bowl until well mixed. Add in the flour mixture to the wet mixture until just combined and set aside. 
3. For banana bread batter: In a medium bowl, mash ripe bananas until smooth and slightly chunky, set aside. In a large bowl combine melted butter with brown sugar until smooth. Add in the eggs and whisk until smooth. To the mixture, add in milk, vanilla extract and mashed bananas until combined. 
4. To the banana batter add in flour, cinnamon, baking soda and salt and gently stir until batter is combined. Do not over mix, batter lumps are okay. Gently fold in the chocolate chips. 
5. Prepare the brownies: Pour in half of the brownie batter to the prepared pan. Scoop in banana bread batter evenly on top of the brownie batter and top with the remaining brownie batter. Gently swirl the batters together on top with a knife. 
6. Bake for 40-45 minutes or a toothpick comes out mostly clean from the center of the brownies. Cool for 15-20 minutes before transferring to a wire rack to cool completely for an additional 15-20 minutes.