Preheat your oven to 350°F (175°C). Grease an 8-inch square baking pan or line it with parchment paper for easy removal.

In a large bowl, mash the ripe bananas until smooth. You’ll want to ensure they’re well-pureed for the best texture.

Add the granulated sugar and melted butter to the mashed bananas. Mix until smooth and well-combined.

Beat in the eggs one at a time, then stir in the vanilla extract until fully incorporated.

In a separate bowl, sift together the all-purpose flour, cocoa powder, baking soda, and salt. Mix thoroughly.

Gradually add the dry ingredients to the banana mixture, stirring until just combined. Be careful not to overmix.

Fold in the chocolate chips and nuts (if using), distributing them evenly throughout the batter.

Pour the brownie batter into the prepared baking pan, smoothing the top with a spatula.

Bake in the preheated oven for 30-35 minutes or until a toothpick inserted in the center comes out with a few moist crumbs.

Once baked, remove from the oven and allow the brownies to cool in the pan for about 10-15 minutes. Then, transfer them to a wire rack to cool completely before cutting.