Preheat your oven to 180°C (350°F). Line a muffin tin with paper liners or grease it well.
Use a fork or potato masher to mash the bananas thoroughly in a large bowl until smooth and jammy, with no large chunks remaining.
Add the oats, honey or maple syrup, eggs, melted butter or oil, vanilla extract, salt, and baking soda to the mashed bananas. Gently fold everything together with a spoon or whisk until just combined, leaving a slightly lumpy batter.
Divide the batter evenly among the 12 muffin cups, filling each about ¾ full to allow room for rising.
Bake in the preheated oven for 20-25 minutes, until the muffins are golden on top and a toothpick inserted into the center comes out clean.
Remove the muffins from the oven and let them cool in the tin for about 5 minutes. Then transfer them to a wire rack to cool completely or serve warm.