Preheat oven to 350℉.
Grease 9"x5" (6-cup) loaf pan. Line with parchment paper. Grease paper.
In medium bowl, mix together dry ingredients (flour, baking soda, baking powder, cinnamon, and nutmeg).
In large bowl, mix together wet ingredients (zucchini, eggs, oil, sugars, vanilla, and salt).
Add dry ingredients to wet ingredients. Mix until well combined.
Place batter in loaf pan.
Sprinkle turbinado sugar on top of batter.
Bake until firm to touch and cake tester comes out clean, approximately one hour.