Preheat oven to 400 degrees F. Line a muffin tin with cupcake liners or coat with non-stick cooking spray. Set aside.
In a medium mixing bowl, stir together flour, baking soda, and salt. Set aside.
In a large mixing bowl, beat together brown sugar and butter until smooth. Add eggs, vanilla, and milk. Mix to combine.
Add dry ingredients and mix until the flour is almost completely incorporated.
In a medium bowl, use a fork to mash bananas. Add in bananas and mix into the batter.
Fill each muffin tin cup 2/3 full with batter. Place in oven and turn heat down to 350 degrees F. Bake for 17-20 minutes or until a toothpick inserted in the center comes out clean.
Remove from oven. Let rest in pan for 5 minutes before transferring to a wire rack. Serve warm or at room temperature.