Preheat your oven to 350°F (175°C) and grease an 8-inch square baking pan or line it with parchment paper.
In a mixing bowl, add the melted butter and mashed bananas, stirring until well combined.
Mix in the granulated sugar, followed by the egg and vanilla extract. Stir until everything is smooth and incorporated.
In a separate bowl, whisk together the flour, baking soda, and salt. Slowly add the dry ingredients to the wet mixture, stirring gently to combine, taking care not to overmix.
Fold in the chocolate chips and nuts (if using) until evenly distributed throughout the batter.
Pour the batter into the prepared baking pan, spreading it evenly with a spatula.
Bake in the preheated oven for about 25-30 minutes or until a toothpick inserted into the center comes out clean.
Allow the cake to cool in the pan for about 10 minutes before transferring it to a wire rack to cool completely.
Notes
Slice the cake into squares and serve warm with a scoop of vanilla ice cream on top, drizzled with chocolate syrup for an indulgent treat!