Preheat the oven to 350°F (180°C).
Line a 9x5-inch loaf pan with parchment paper, leaving some overhang on the sides.
If not using a silicone pan, grease the pan with butter and dust with flour.
Peel and break the bananas into pieces.
Mash them with a fork until mostly smooth; small lumps are okay.
In a mixing bowl, beat the eggs with brown sugar, salt, oil, and vanilla extract until well combined.
Stir the mashed bananas into the wet mixture until fully incorporated.
In a separate bowl, sift together the all-purpose flour, cinnamon, and baking powder.
Gradually add the dry ingredients to the wet mixture, mixing gently.
Stir just until everything is combined; avoid overmixing.
Gently fold the coarsely chopped walnuts into the batter.
Pour the batter into the prepared loaf pan.
Bake in the preheated oven for 50 minutes, or until a toothpick inserted in the center comes out clean.
Remove the bread from the oven and let it cool in the pan for about 10 minutes.
Lift the bread out using the parchment paper overhang.
Slice when slightly cooled and enjoy!