Spray a 9 X 5 bread pan with vegetable spray. Heat your oven to 350F.
Cut off the ends of the Zucchini and shred it (including the peel), until you have 1 1/2 cups of shreds. Place the shredded zucchini in 2 - 3 paper towel pieces and then wring it out over the sink, to remove excess fluid.
In a small bowl, combine the ground flax seeds and water. Stir to combine.
In a mixing bowl, combine the vegan butter, coconut sugar, plant-based milk (if not using vanilla-flavored add 1 teaspoon of vanilla), and apple cider vinegar. Stir to combine. Add the pressed zucchini and stir this all together.
In a separate bowl, combine the flour, baking soda, cinnamon, and salt. Stir to combine. Add the dried cranberries and chopped walnuts (if using). Stir until both are coated.
Pour the wet ingredients into the dry and stir until just combined.
Pour the batter into your prepared bread pan. Place in the heated oven and bake for 50 minutes, or until a tester inserted in the center comes out clean.
If your plant-based milk is not vanilla-flavored, add 1 - 2 teaspoons of vanilla extract.