Preheat and prep the pan. Heat the oven to 350°F (175°C). Grease a 9x5-inch loaf pan or line it with parchment so the paper hangs over the long sides for easy lifting.

Mash the bananas. In a large bowl, mash the bananas with a fork until mostly smooth with a few small lumps. You should have about 1 cup.

Whisk in the wet ingredients. Add the sugar, melted butter (or oil), egg, and vanilla. If using milk or yogurt, add it now. Whisk until the mixture looks glossy and combined.

Add the dry ingredients. Sprinkle the flour, baking soda, salt, and cinnamon over the wet mixture. Gently fold with a spatula until the flour just disappears. Do not overmix—a few streaks are fine.

Fold in mix-ins. If using chocolate chips or nuts, fold them in with a few light turns. Keep the batter thick and airy.

Fill the pan. Scrape the batter into the prepared loaf pan and smooth the top. For a pretty finish, sprinkle a pinch of sugar over the surface or add a few extra chocolate chips.

Bake. Place on the center rack and bake for 50–60 minutes. Start checking at 48 minutes. The loaf is done when a toothpick inserted in the center comes out clean or with a few moist crumbs.

Cool. Let the loaf cool in the pan for 10–15 minutes, then lift it out and cool on a rack until just warm. Slice with a serrated knife for neat pieces.

Serve. Enjoy plain, with butter, or a swipe of peanut butter. Warm slices are especially good.