Preheat the oven to 180C/350F/Gas 4. Line an 8x8-inch square baking pan with foil or parchment paper, and set aside.

Place the butter, sugar, cocoa powder, and salt into a microwave-safe bowl, and microwave in 30 second intervals, stirring after each one, until the butter is melted and the mixture feels very warm to the touch.

Mix in the eggs, one at a time, then the vanilla and TWO mashed bananas. Fold in the flour until fully combined. Fold in the chocolate chips.

Pour the batter into the prepared pan and spread out evenly. Slice the remaining bananas in half lengthwise, and place on top of the batter.

Bake for 45 - 50 minutes, or until the centre is no longer jiggly and a toothpick inserted comes out almost clean with a few moist crumbs. You may cover the pan loosely with foil past the 30 - 40 minute mark to prevent excessive browning.

Allow to cool completely in the pan on a wire rack before cutting into bars. I refrigerated my brownies before slicing for extra neat, clean cuts.