Preheat oven to 350 degrees. Line a bread pan with foil and coat with cooking spray.
In a large bowl combine the zucchini, sugar, vanilla, eggs and stir together until well combined.
Add flour, baking soda, cinnamon, salt and baking powder to a bowl and which to combine. Add the dry ingredients to the wet ingredients and mix until well combined.
In a small bowl combine the cinnamon and sugar for the cinnamon swirl.
Pour a 1/3 of your batter into the prepared bread pan. Sprinkle a 1/3 of the cinnamon mixture over the batter. Add another 1/3 of the batter and the remaining cinnamon mixture. Top with the remaining batter. (Feel free to swirl the cinnamon-sugar mixture around with a knife to incorporate into the batter more)
Bake for 35-45 minutes until a toothpick inserted comes out clean.