01 - Preheat oven to 350°F. Grease and line a 9-inch square or round cake pan.
02 - In a large mixing bowl, whisk together mashed bananas, eggs, vegetable oil, granulated sugar, light brown sugar, and vanilla extract until homogenous.
03 - In a separate bowl, whisk all-purpose flour, baking soda, baking powder, ground cinnamon, and salt until evenly distributed.
04 - Gradually add dry ingredients to wet mixture, stirring gently until just combined. Take care not to overmix.
05 - Gently fold in chopped walnuts or pecans and chocolate chips, if using.
06 - Pour batter into prepared pan and smooth the top with a spatula.
07 - Bake for 35 to 40 minutes, or until a toothpick inserted in the center emerges clean.
08 - Allow cake to cool in the pan for 10 minutes. Transfer to a wire rack to cool completely before serving warm or at room temperature.