Preheat your oven to 350°F (175°C) and grease a standard loaf pan or line it with parchment paper.
In a bowl, mash the ripe bananas until mostly smooth.
Add melted butter (or oil), sugar, eggs, and vanilla. Mix until combined.
In another bowl, whisk together flour, baking soda, baking powder, salt, and cinnamon (if using).
Add the dry ingredients into the banana mixture and stir gently. Do not overmix.
Fold in chocolate chips or walnuts if you like.
Pour the batter into your loaf pan and smooth the top.
Bake for 50–60 minutes, or until a toothpick inserted in the center comes out clean.
Let the banana bread cool in the pan for 10 minutes, then transfer to a wire rack to cool fully.
Slice and enjoy