Add eggs, sourdough starter, yogurt, maple syrup, vanilla, and butter to a large mixing bowl and combine well with a hand mixer.
In a separate bowl, add flour, baking powder, baking soda, and 1/2 teaspoon of salt and combine well.
Add dry ingredients to bowl of wet ingredients and combine well, until a thick batter is formed.
Cover bowl with a damp cloth or plastic wrap and let ferment at room temperature for about 5 hours.
While the batter is fermenting, prepare the zucchini:
Grate zucchini (using the largest holes of a box grater) into a large bowl.
Sprinkle grated zucchini with 1/2 teaspoon of salt and combine, then transfer grated zucchini to a colander set over a large bowl let rest for about 30 minutes.
Squeeze out the excess liquid from the grated zucchini.
After the batter has fermented, preheat oven to 350 degrees Fahrenheit.
Fold prepared zucchini into the batter.
Line a loaf pan with parchment paper, then transfer batter to the prepared loaf pan.
Bake in the center of the preheated oven for about one hour, or until the top is slightly golden brown and a knife comes out clean when inserted into the center of the bread.
Remove from the oven and transfer to a wire rack to cool.
Let cool for at least 30 minutes before slicing into (it's still cooking!)
Enjoy!