Preparation Steps

• Preheat your oven to 350°F (175°C) and grease a 9x13 inch baking dish. In a mixing bowl, cream together the sugar and softened butter until light and fluffy. Gradually mix in the mashed bananas and beat in the eggs, one at a time.
• In another bowl, whisk together the flour, baking powder, baking soda, and salt. Slowly incorporate the dry ingredients into the banana mixture until just combined. Stir in the chopped walnuts if using.
• Pour the batter into the prepared baking dish, spreading it evenly. For the crumble topping, combine some flour, sugar, and butter in a separate bowl, mixing until crumbly. Sprinkle this mixture generously over the top of the batter.
• Bake for about 45 to 50 minutes, or until a toothpick inserted in the center comes out clean. Allow it to cool before cutting into squares and serving.