2 cups whole grain flour (wheat, spelt or any combination of the two)
3 tsp cinnamon
2 tsp baking soda
2 tsp baking powder
1/4 tsp nutmeg
Preheat oven to 350F. Line two 12-cup muffin tins with silicone baking cups or traditional muffin liners.
Grate zucchini using a grater or food processor. Combine zucchini and salt in a large colander and mix well. Allow to stand for 10 minutes. Press as much liquid out of the zucchini as possible while in the colander. Then, squeeze all the water out of the zucchini (see method in-post).
Meanwhile, melt butter in a large bowl. Measure honey and maple syrup to the butter and mix well.
Add eggs and vanilla and mix well.
Finally, add shredded carrot, apple and zucchini and stir to combine very well.
In a separate small bowl, mix all the flours, baking soda, baking powder, cinnamon and nutmeg and combine well.
Add half of the dry ingredients to the wet ingredients and stir to barely combine, approximately 5 big rounds of the bowl.
Add the remaining dry ingredients to the bowl and stir to just barely combine, another 5-7 big rounds of the bowl.
Use a muffin scoop to divide the batter between the 24 muffin cups and bake for 20-25 minutes, until a knife inserted in the center comes out clean.