Preheat your oven to 350°F (175°C) and grease a 9×5 inch loaf pan.

In a medium bowl, whisk together the flour, baking soda, baking powder, salt, cinnamon, and nutmeg.

In a large mixing bowl, beat the vegetable oil, granulated sugar, and brown sugar until smooth. Add eggs one at a time.

Stir in the grated zucchini and vanilla extract until well combined.

Gradually mix the dry ingredients into the wet ingredients until just combined. Fold in nuts if using.

In a small bowl, mix together a couple tablespoons of sugar with a teaspoon of cinnamon to create the cinnamon sugar.

Pour half of the batter into the loaf pan, sprinkle half of the cinnamon sugar, then add the remaining batter and sugar.

Gently swirl through the batter with a knife to create a marbled effect.

Bake for 55 to 65 minutes, checking for doneness with a toothpick.

Let the zucchini bread cool in the pan for about 10 minutes before transferring to a wire rack to cool completely.