Preheat oven to 350 degrees. Butter and flour a large 9" bread pan and set aside. Whisk together flour, cinnamon, baking soda, and salt in a small bowl until combined. Set aside.
In a stand mixer or using a hand mixer, beat together sugars, oil, and eggs for about 1-2 minutes until slightly fluffy. Add vanilla and sour cream.
Fold in the grated zucchini. Add the remaining dry flour ingredients. Stir to combine and pour into prepared 9" bread pan. Bake for 50-60 minutes. I set a time for 45 minutes and mine was done at that time. Oven temperatures vary, so just make sure a toothpick entered in the center comes clean.
Let cool for about 5-10 minutes and remove from pan. Delicious served a little warm, even with a little butter on top. 🙂