Preheat your oven to 350°F (175°C). Grease a 12-cup muffin pan or line it with paper liners.
In a large mixing bowl, whisk together the flour, oats, baking soda, cinnamon, and salt.
In another bowl, mash the bananas until smooth. Add the eggs, honey, olive oil, milk, and vanilla extract. Whisk until well combined.
Pour the wet ingredients into the dry ingredients and stir gently until just combined. Avoid overmixing to keep the muffins tender.
Fold in any optional mix-ins such as walnuts or chocolate chips.
Divide the batter evenly among the muffin cups, filling each about three-quarters full.
Sprinkle extra oats and a pinch of cinnamon over each muffin.
Bake the Healthy Banana Oatmeal Muffins for 20–25 minutes, or until a toothpick inserted into the center comes out clean.
Let the muffins cool in the pan for 5 minutes before transferring them to a wire rack.