Preheat Oven – Preheat oven to 350°F (175°C). Grease a 9x5-inch loaf pan or line it with parchment paper.
Mash Bananas – In a bowl, mash the ripe bananas with a fork until smooth.
Mix Wet Ingredients – Add melted butter (or oil), brown sugar, eggs, and vanilla extract. Whisk until combined.
Add Dry Ingredients – Sift in flour, baking soda, salt, and cinnamon (if using). Gently fold until just combined (do not overmix).
Fold in Nuts – Stir in chopped walnuts or pecans.
Bake – Pour batter into the prepared pan and bake for 50-60 minutes, or until a toothpick inserted comes out clean.
Cool – Let it cool in the pan for 10 minutes, then transfer to a wire rack.
