Preheat your oven to 350°F (175°C). Grease a 9×5-inch loaf pan and line with parchment for easy removal.

In a medium bowl, whisk together the flour, baking soda, salt, and cinnamon.

In a large bowl, whisk the melted butter and brown sugar until glossy and slightly aerated. Add the eggs one at a time, whisking until smooth. Stir in the vanilla.

Mash the bananas with a fork until mostly smooth — small lumps are charming and keep the loaf moist.

Fold the mashed bananas and Greek yogurt into the butter mixture until streaks of batter come together.

Gently fold the dry ingredients into the wet mixture just until combined.

Fold in walnuts or chocolate chips if using.

Pour batter into the prepared loaf pan, smoothing the top with a spatula.

Bake for 55 to 65 minutes, rotating halfway, until a toothpick inserted into the center comes out with a few moist crumbs.

Let the loaf cool in the pan for 10 minutes, then lift it out using the parchment and cool on a wire rack.