Pre-heat the oven to 350° F and grease a loaf pan with cooking spray.
Using a mixer, mash the bananas.
Cream (or mix) the sugar into the bananas.
Add the egg to the sugar mixture, mixing well.
In a separate mixing bowl, whisk together the flour, baking soda, baking powder, and salt.
Mix the dry ingredients and the canola oil into the sugar mixture.
Gently fold the walnuts into the bread batter by hand, mixing them in well.
Scrape the batter into the prepared loaf pan.
Sprinkle with extra walnuts, if desired.
Bake at 350° F for about 1 hour, or until a toothpick inserted into the center comes out clean and the loaf is golden brown.
Let it cool in the pan for 10 to 15 minutes; then run a butter knife around the edge, and plop it out onto a wire rack to cool completely.
Slice and serve your banana loaf with dairy free butter– or regular butter if you're not dairy free.