Preheat the oven to 350°F (175°C) and line a muffin tin with liners or lightly grease it with cooking spray.
Add and combine the flour, baking powder, cinnamon, baking soda, and salt I a mixing bowl. Mix well.
In another bowl, combine the grated zucchini, carrots, coconut sugar, melted coconut oil, almond milk, and vanilla extract. Stir until well combined.
Slowly incorporate the dry ingredients into the wet ingredients, mixing until they are just combined. Avoid overmixing, as it can make the muffins dense.
If using, fold in the chopped walnuts or raisins.
Using a spoon, spread the batter into the prepared muffin tin, ensuring each cup is filled approximately three-quarters full.
Place the muffin tin in the preheated oven and bake for 18-20 minutes or until a toothpick inserted into the center of a muffin comes out clean, indicating they are fully cooked.
Take the muffins out of the oven and allow them to cool in the muffin tin for a few minutes. Then, carefully transfer the muffins to a wire rack to cool completely.