Prep the pan and oven: Heat your oven to 350°F (175°C).
Grease a 9x5-inch loaf pan and line it with a parchment sling for easy removal.
Mash the bananas: In a large bowl, mash the bananas with a fork until mostly smooth. A few small lumps are fine; they add texture and moisture.
Whisk in wet ingredients: Add melted butter, brown sugar, eggs, yogurt (or sour cream), and vanilla. Whisk until the mixture looks glossy and well combined.
Mix dry ingredients separately: In another bowl, whisk flour, baking soda, salt, and cinnamon.
This helps distribute the leavening evenly.
Combine gently: Add the dry ingredients to the wet. Use a spatula to fold until just combined. Do not overmix—a few flour streaks are okay.
Add chocolate chips: Fold in the chocolate chips, reserving a small handful for the top.
Fill the pan: Pour the batter into the prepared loaf pan. Smooth the top and sprinkle on the extra chips.
Bake: Bake for 55–65 minutes, until a toothpick inserted near the center comes out with a few moist crumbs.
If the top browns too quickly, tent with foil for the last 10–15 minutes.
Cool properly: Let the loaf cool in the pan for 10–15 minutes. Lift it out and cool completely on a wire rack before slicing. This helps set the crumb and prevents crumbling.
Slice and enjoy: Use a serrated knife for clean slices.
Serve warm, at room temperature, or lightly toasted with butter.