Preheat the oven to 350°F (180°C). Spray a 9x5 loaf pan with non-stick spray and line the bottom with parchment paper.
Sift the all purpose flour into a mixing bowl and add the white granulated sugar, light brown sugar, baking powder, cinnamon, nutmeg and salt. Mix together.
Prepare your flax egg by mixing 1 Tbsp Ground Flaxseed Meal with 3 Tbsp Hot Water and allow to sit for a minute to become gloopy.
Add the flax egg, shredded zucchini, mashed banana, soy milk, melted coconut oil and vanilla extract to the mixing bowl and mix in briefly. It will seem like there is not enough wet ingredients to mix in properly, don't worry. Leave the mixing bowl for a couple of minutes. When you come back to it the zucchini will have released more water into the mix and you should be able to form it into a thick batter. Mix it in properly, but don't overmix.
Add chopped walnuts and mix in.
Transfer to your prepared loaf pan and smooth down evenly. Add a few chopped walnuts directly to the top of the bread before baking.
Place into the oven and bake for 60 minutes or until a toothpick inserted into the center comes out clean.
Let the bread cool for a few minutes before removing it from the pan and placing onto a wire cooling rack to cool completely.