Preheat your oven to 180°C (350°F). Grease a 20x10cm loaf tin and line it with parchment paper.

In a large mixing bowl, whisk together the flour, sugar, baking powder, and salt. The mixture should be well-combined and have a light, airy texture.

In a separate bowl, whisk together the melted butter, eggs, and vanilla extract. The mixture should be smooth and creamy.

Add the mashed bananas to the wet ingredients and whisk until well-combined. The mixture should be thick and creamy, with a sweet aroma.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Do not overmix. The mixture should be thick and chunky, with a sweet, banana scent.

Pour the batter into the prepared loaf tin and smooth the top. If using walnuts, sprinkle them on top of the batter.

Bake for 55 minutes, or until a toothpick inserted into the centre of the bread comes out clean. The bread should be golden brown, with a firm texture and a sweet, caramelised aroma.

Remove the bread from the oven and let it cool in the tin for 10 minutes. Then, transfer it to a wire cooling rack to cool completely. The bread should be warm, with a gentle crust and a soft, fluffy interior.