Preheat your oven to 350°F (175°C). Grease a 9x5 inch loaf pan with oil.

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

In a larger bowl, whisk together oil, granulated sugar, and brown sugar until smooth. Add eggs one at a time and then vanilla extract.

Fold in zucchini until evenly mixed.

Gently fold the dry mixture into the wet ingredients until just incorporated. Add nuts if desired.

Mix together sugar and cinnamon for the swirl. Set aside.

Pour half the batter into the prepared loaf pan. Sprinkle with half the cinnamon sugar, then add the remaining batter and top with remaining sugar.

Use a butter knife to gently swirl through the batter.

Bake for 55 to 65 minutes until a toothpick comes out clean.

Let the bread cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.