Preheat the oven to 375°F (190°C) and grease a standard 12-cup muffin tin or line with paper liners.

In a large mixing bowl, mash the bananas with a fork or whisk until smooth.

Whisk the melted butter into the mashed bananas until fully incorporated.

Add the sugar, egg, and vanilla extract to the bowl and stir until combined.

Sprinkle the baking soda and salt over the wet mixture and stir well.

Add the flour to the bowl and stir with a spatula until just combined, ensuring no dry streaks remain without overmixing.

Fold in 3/4 cup of the chocolate chips into the batter.

Distribute the batter evenly among the 12 muffin cups and sprinkle the remaining 1/4 cup of chocolate chips on top.

Bake for 18 to 20 minutes, or until a toothpick inserted into the center of a muffin comes out clean.

Allow muffins to cool in the pan for 5 minutes before transferring to a wire rack to cool completely.