Set your oven to 350 degrees F and arrange a muffin tin with liners or grease it well.
In a big bowl, mash the bananas until they become smooth. Whisk in the egg, honey, and cooled melted coconut oil until the mixture is uniform.
Add oat flour, protein powder, baking powder, baking soda, cinnamon, and ginger to the banana mixture and stir everything together gently. If you like, fold in the dark chocolate chips.
Distribute the batter evenly into muffin cups, filling each about three-quarters full. Avoid overfilling.
Bake the muffins for about 15 minutes or until their tops turn golden and a toothpick inserted in the center comes out clean.
Let the muffins rest and cool in the pan for five minutes before taking them out.