Preheat the oven to 350°F (175°C) and grease a 24-cup mini-muffin tin.
In a large bowl, mash the bananas until smooth, then stir in the melted butter.
Add the baking soda and salt, then stir in the sugar, beaten egg, and vanilla extract.
Gently fold in the flour until just combined, ensuring no dry pockets remain.
Divide the batter evenly among the prepared mini-muffin cups, filling each approximately 3/4 full.
Bake for 12 to 14 minutes, or until a toothpick inserted into the center comes out clean.
Allow the bites to cool in the tin for 5 minutes before transferring to a wire rack to cool completely.