Makes two bread-sized or pound cake-sized loaves.
Preheat the oven to 350F degrees.
Wash and cut off the ends of your zucchini. Coarsely grate the zucchini. Use the zest grate on a standard cheese grater (or a lemon zester tool) to grate the zest off of one lemon.
Beat the eggs with a whisk until fluffy. Add the vanilla, sugar, oil, lemon zest, and zucchini.
In another bowl, mix in your flour, salt, baking soda, baking powder (ideally with a sift).
Add the wet mixture to your dry mixture and incorporate. Add the nuts and give the batter a final mix.
Butter and flour two pound cake (or bread loaf) forms. Pour your batter into the forms. Lay a few walnut halves onto both cakes.
Cover in foil and bake at 350F for about 1 hour until the cake no longer jiggles when you shake it and until a knife comes out cleanly. If you're using one large cake dish, instead of two loaves, bake for ~90 minutes.
Remove the foil for the last ten minutes of baking. Removing the foil will make the top cook much faster, so if you desire a crunchier top, remove the foil sooner.
When the cakes are cooked, squeeze the juice of one lemon over them (1/2 lemon per loaf), and garnish with sprinkled sugar or lemon zest.