Preheat your oven to 350°F (175°C).

Grease an 8x8 inch baking dish or line it with parchment paper.

In a mixing bowl, mash the very ripe bananas until smooth.

Add the melted butter, light brown sugar, vanilla essence, and egg into the bowl with the mashed bananas. Stir until well combined.

In another bowl, whisk together the whole wheat flour, baking soda, and salt. Gradually add this dry mixture into your wet ingredients. Stir until everything is incorporated.

Gently fold in the semi-sweet chocolate chips (or nuts if you opted for those).

Pour the batter into your prepared baking dish and spread it evenly. Bake for about 30 minutes or until a toothpick inserted in the center comes out clean.

Once baked, let cool in the pan for about 10 minutes before transferring to a wire rack. Allow to cool completely before slicing into squares.