In a large bowl, combine the eggs and sugars and whisk until smooth.
Add in the vanilla, sour cream, and oil. Mix until fully combined.
Add the flour, baking powder, baking soda, salt, and cinnamon. Stir until the batter just comes together.
Shred the zucchini, then squeeze out the excess water using a cheesecloth (or a clean kitchen towel).
Fold the zucchini and walnuts into the batter until evenly distributed.
Pour the batter into a greased loaf pan and bake at 375°F for 60 minutes, or until a toothpick comes out clean.