Preheat the oven to 400 degrees F. Line a 12 cup muffin tin with muffin liners and spray the inside of the liners with nonstick cooking spray.
In a large bowl, whisk together the wet ingredients: mashed bananas, honey, eggs, milk, and vanilla extract until smooth and well combined.
In a separate large bowl whisk together the dry ingredients: whole wheat pastry flour, wheat bran, baking powder, cinnamon and salt. Add the dry ingredients to the wet ingredients and mix with a wooden spoon until just combined.
Stir in melted butter, mixing again until smooth and well combined. Fold in the walnuts.
Divide batter evenly into muffin liners and sprinkle with extra walnuts. Bake for 15 to 20 minutes or until the toothpick comes out clean or with just a few crumbs attached.
Cool muffins for 5 to 10 minutes then remove and transfer to a wire rack to finish cooling. Muffins are best served warm with a little butter, honey and a sprinkle of sea salt on top.
