Gather all the ingredients. Preheat oven to 350 F. Prep the muffin pans with non-stick spray and set aside.
Melt butter in a large microwave-safe bowl.
Peel and add ripe bananas into the melted butter and mash into chunks.
Add the eggs into the mixture and add vanilla extract. Mix well.
In a separate large bowl, add all the dry ingredients except for the chocolate chips and nuts -flour, sugar, baking soda, cinnamon and salt. Whisk to combine thoroughly.
Add the combined dry ingredients in bowl 2 to the prepared wet ingredients in the first bowl. Use a spatula to gently mix till combined. If you are planning to use chocolate chips and chopped nuts, add in now. Do not overmix.
In the prepared muffin pans, evenly divide the batter.
This is purely optional: Slice banana into thin discs and put on top of each muffin. You can also add one or two chocolate chip on top for a loaded treat!
Pop the filled pans into the preheated oven and bake for 30 - 35 minutes, or until the tops are golden brown.
When done, remove from pan and let cool in rack. Enjoy!