Pre-heat the oven to 350 degrees. Grease and flour three 7-inch cake pans* See Notes for alternative size pans.
Whisk together the flour, both sugars, lemon zest, baking powder, baking soda, salt, cinnamon, and cardamom in a large bowl.
In a separate bowl or large liquid measuring cup, add in the oil, eggs, and buttermilk. Whisk to break the egg yolks and combine.
Make a well in the center of the dry ingredients. Stream in the wet ingredients into the center of the bowl and begin whisking the batter to combine As the batter comes together, switch to a rubber spatular to stir. Before the last streaks of the dry ingredients disappear, fold in the zucchini.
Evenly distribute the batter into the prepared pans and smooth out the tops. Bake in the preheated oven for 23 to 25 minutes, or until a toothpick inserted into the center of the cakes comes out clean. Cool cakes on a wire rack for 10 to 15 minutes before removing them from their pans. Continue to cool completely before cutting or filling.
*May also be baked in four, 6-inch cake pans for 24 to 26 minutes or two, 8 or 9-inch cake pans for 25 to 30 minutes.