Preheat oven to 325 degrees.
In the bowl of a mixer add beaten eggs, oil, both types of sugar, zucchini, and vanilla. Mix on low until combined and mixed well.
Then on medium speed slowly add dry ingredients: flour, salt, baking soda, baking powder and cinnamon until combined.
Spray the inside of two 9×5 loaf pans with non-stick cooking spray. Pour half the prepared batter into one of the loaf pans and tap the pans on the counter to release the bubbles inside the batter.
Add the zest and lemon juice to the remaining batter and mix well. Add 1 tbs of flour to firm up the batter. Add the lemon batter to the 2nd loaf pan and tap it on the counter to remove bubbles. Place both loaves on a sheet pan.
Bake for 60 minutes until crust is golden brown and a cake tester or toothpick comes out clean. Cool on a wire rack. Slice and enjoy with a nice creamy smear of fresh butter.