Position a rack in the middle of the oven. Preheat the oven to 350°F (176 °C).

Butter and flour an 8 ½-inch by 4 ½-inch loaf pan. Or grease the pan and then line it with a sheet of parchment paper.

Whisk the flour, baking soda, salt, and cinnamon together and set aside.

Use a fork to mash the bananas into a chunky paste in the bottom of a large bowl.

Whisk the melted butter, brown sugar, eggs, and vanilla into the bananas until well blended.

Switch to a large rubber spatula, scrape the sides and bottom of the bowl, and then add the dry ingredients in two parts, stirring until the flour disappears and the batter is smooth. Fold in the chocolate chips, saving a handful to add to the top of the loaf.

Pour batter into the prepared pan and smooth the top. Scatter the reserved chocolate chips over the top.

Bake for 55 to 65 minutes, or until a thin knife inserted into the center of the bread comes out clean.

Transfer to a wire rack to cool for 5 minutes. Unmold the bread and cool completely before slicing.