Chocolate Chip Banana Bars (modified from Gimme Delicious)

• Preheat the oven to 350°F / 175°C. Line an 8x8-inch baking dish with parchment paper and spray with cooking spray. Set aside.
• In a large bowl or the bowl of a stand mixer, cream together ½ cup unsalted butter and 1 cup brown sugar with a stand mixer or hand mixer. Mix on a medium-high speed for about 2 minutes, until the mixture becomes lighter in color. You can also make this batter by hand with a whisk, but the butter will need to be quite soft.
• Add in 1 large egg, 1 ½ teaspoon vanilla extract, and ½ teaspoon fine salt. Mix on a medium-low speed until combined. Scrape the sides and bottom of the bowl as needed with a rubber spatula.
• Mix in 1 cup of all-purpose flour and mix on low until just combined.
• Fold 1 cup mashed banana into the batter until they're fully incorporated.
• Then fold in ¾ cup mini chocolate chips or chopped chocolate chips, saving a few to sprinkle on top of the batter before they're baked.
• Pour the batter into the prepared pan and sprinkle a few additional bits of chocolate on top of the batter.
• Bake for 33-37 minutes, until the edges are golden brown, and the center is baked through. Rotate the pan halfway through to help the bars bake evenly.
• Remove the pan from the oven and let it cool on a wire rack. Let the bars fully cool in the pan. Once cool, gently remove the bars from the pan and cut into 16 squares using a sharp, warm knife. Wipe the blade after each cut with a paper towel to get nice, clean cuts.
• These bars can sit at room temperature for a few days or be covered with plastic wrap or stored in an airtight container in the fridge for up to a week.