Preheat your oven to 350°F and line or lightly grease a muffin tin.
Combine oats, flour, baking powder, soda, and salt in a bowl and whisk to combine.
In a second bowl, combine sugar, banana, vanilla, the egg, and oil and beat with a whisk by hand until smooth and combined.
Combine the wet and dry ingredients, folding gently until most of the flour is absorbed. Add in the chocolate chips then continue to fold until everything is combined and mixed, then stop.
Scoop into the muffin tin and bake for 15 minutes or until a toothpick comes out cleanly, or the tops gently spring back under a light pressure.
Remove from pan to cool. Store for 3 days on the counter, or up to 3 months in the freezer.
Notes
*Whole wheat or AP flour work well too. If using AP, reduce oil by 2 tablespoons or 30 ml *I always provide weight measurements on my baking recipes, these are the weights I measure, and the volume I measure, not a google estimate. Please use weight it possible for best accuracy.