Preheat oven to 350.
Mix all your dry ingredients (except the baking powder and baking soda, and chocolate chips) in a small bowl.
In your mixing bowl, mash the bananas with a fork or potato masher- a few chunks are ok if you like them (I like them). Add the melted butter (or ghee, oil, or coconut oil) and vanilla if using.
Add dry ingredient mix to wet.
Let the mixture hydrate for 15 minutes or so (these will be fine if you don't, but are extra fluffy if you do).
Line your muffin tins with paper liners or grease them.
When batter is hydrated add the baking powder and soda and mix well, add chocolate chips if desired. I usually either add cinnamon or chocolate - I don't like them together - but you do you.
Fill the muffin cups basically to the top (maybe 1/4 inch from the top) they will dome up but not overflow and muffin tops are the best.
Bake about 20 minutes. I'd check them after 15. A classic toothpick test works - it should come out cleanish or a few wet but set crumbs. Or simply make sure they are firm to the touch and out they come to
Cool for as long as you can stand it before eating them.