Preheat the oven to 350°F (175°C). Line a muffin pan with liners or lightly grease it.
In a large bowl, mash the bananas until mostly smooth.
Add eggs, milk or oil, sugar, and vanilla to the bananas. Mix until combined.
In a separate bowl, whisk together flour, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients.
Gently fold everything together just until combined. Do not overmix.
Stir in the finely chopped nuts, if using.
Divide the batter evenly among the muffin cups, filling each about 3/4 full.
Bake for 20 to 22 minutes, or until the tops are golden and a toothpick inserted comes out clean.
Remove from oven and let muffins cool in the pan for 5 minutes.
Transfer to a wire rack and cool completely before serving.
