Preheat your oven to 350°F and prepare a muffin tin by lining it with cupcake liners or coating the cavities with non-stick spray.
Shred the zucchini using a food processor or cheese grater, then squeeze out the excess liquid using a clean towel. Set aside.
In a large mixing bowl, mash the banana and applesauce together until smooth.
Add almond milk, vanilla extract, and squeezed shredded zucchini to the bowl, and mix well.
Incorporate oat flour, baking powder, cinnamon, salt, and ground flax into the wet mixture, and whisk until fully combined. Set aside.
Fold in dark chocolate chips and chopped walnuts until evenly distributed throughout the batter.
Pour the batter into the prepared muffin tin, filling each cavity almost to the top.
Bake for 25-30 minutes, or until a toothpick inserted into the center of a muffin comes out clean and the tops are golden brown.
Once baked, remove the muffins from the oven and allow them to cool before serving.