Step 1: Preheat the Oven: Preheat your oven to 350°F (175°C). Ensure your oven rack is set to the center position for even baking.
Step 2: Prepare the Loaf Pans: Lightly grease two 8x4-inch loaf pans with avocado oil, neutral oil, or butter. Alternatively, line the pans with parchment paper, leaving a bit of overhang on the sides for easy removal later.
Step 3: Shred the Zucchini: Wash the zucchinis thoroughly and trim off the stems. Using the coarse side of a box grater or the shredding attachment of a food processor, grate the zucchini completely down, leaving the skin on.
Step 4: Squeeze Out Excess Juice: Place the grated zucchini into a clean kitchen towel or a few layers of cheesecloth. Wring and twist the towel over the sink to squeeze out the excess natural liquids, then measure out your 3 cups of squeezed shreds.
Step 5: Whisk the Dry Base: In a large mixing bowl, combine the all-purpose flour, baking powder, baking soda, fine sea salt, and ground cinnamon. Stir thoroughly with a whisk or wooden spoon until the spices are evenly distributed.
Step 6: Create a Well: Use your spoon to push the dry ingredients toward the edges of the bowl, creating a large hole or "well" directly in the center.
Step 7: Add the Wet Ingredients: Pour the light olive or avocado oil, room-temperature eggs, vanilla extract, and your squeezed, grated zucchini right into that center well.
Step 8: Mix the Batter: Using a spoon or spatula, stir strictly by hand starting from the center well. Gradually pull the dry flour from the edges into the wet center. Mix just until the ingredients are incorporated and no dry white streaks remain.
Step 9: Fold in the Mix-Ins: Gently fold your mini chocolate chips (and optional chopped walnuts or pecans) into the thick batter with a spatula until they are evenly distributed throughout. Do not overmix.
Step 10: Pour Into Pans: Divide the thick batter equally between your two prepared loaf pans, smoothing the tops with your spatula.
Step 11: Bake the Bread: Bake on the center rack for 45 minutes. Test the center of the loaves with a toothpick; it should come out clean or with a few dry crumbs attached.
Step 12: Cool and Slice: Let the loaves cool inside their pans for 10 minutes. Then, carefully turn them out onto a wire cooling rack to cool completely to room temperature before slicing.