Banana Bread Brownies

Preheat the oven to 350°F (175°C) and line a 9x9-inch square baking pan with parchment paper.
In a large bowl, use an electric mixer or whisk to beat ¾ cup unsalted butter, 1 cup granulated sugar, and ½ cup brown sugar together until smooth. Add 3 large eggs and 2 teaspoons vanilla extract and mix until fully combined.
Stir in ¾ cup all-purpose flour and ½ teaspoon salt, mixing just until combined.
In a separate medium bowl, mash 1 cup over-ripe mashed bananas and sprinkle ½ teaspoon baking powder on top. Stir to combine, then add half of the prepared batter into the banana mixture and stir to combine. Set aside.
Add ½ cup unsweetened cocoa powder and ¾ cup semisweet chocolate chips into the remaining half of the batter mixture. Stir to combine.
Dollop spoonfuls of about half of the brownie batter into the prepared pan. It doesn’t need to cover the bottom completely. Pour the banana bread mixture over the brownie mixture, spreading it evenly. Drop spoonfuls of the remaining brownie batter on top, then use a knife to gently swirl the two mixtures together.
Sprinkle 2 tablespoons semisweet chocolate chips on top before baking.
Bake for 40 to 45 minutes or until a toothpick inserted into the center comes out clean with just a few crumbs attached. Let cool completely before slicing into squares.