Preheat the oven to 350°F (175°C) and line a muffin tin with paper liners.
In a large mixing bowl, mash the ripe bananas with a fork until smooth.
Add the softened butter, granulated sugar, and brown sugar into the mashed bananas and mix until well combined.
Beat in the eggs one at a time, then add the vanilla extract and mix until smooth.
In another bowl, whisk together the all-purpose flour, baking soda, baking powder, salt, and ground cinnamon.
Gradually add the dry ingredients to the wet mixture, stirring gently with a rubber spatula until just combined. Be careful not to overmix.
If desired, fold in the chopped walnuts or pecans for added texture.
Divide the batter evenly among the muffin cups, filling each about ⅔ full.
Bake in the preheated oven for 18-20 minutes or until a toothpick inserted into the center of a muffin comes out clean.
Once baked, remove from the oven and allow to cool in the pan for about 5 minutes. Then transfer the muffins to a cooling rack to cool completely.