Preheat your oven to 350°F (175°C) and grease a baking dish.
Mash 2-3 overripe bananas in a bowl until smooth.
Add 1/3 cup melted butter, 1 beaten egg, 1 teaspoon vanilla extract, and 1/2 cup sugar to the bowl and mix well.
In a separate bowl, mix 1 cup flour, 1/2 teaspoon baking powder, 1/2 teaspoon baking soda, and 1/4 teaspoon salt.
Combine the dry ingredients with the wet ingredients and mix until well combined.
Fold in 1/2 cup chocolate chips and pour the batter into the greased baking dish.
Bake for 25-30 minutes or until a toothpick comes out clean. Let cool before serving.