Preheat the Oven: Set your oven to 350°F (175°C). Prepare a 9×5-inch loaf pan by lining it with parchment paper, leaving an overhang for easy removal.

Mix Butter and Sugar: In a large mixing bowl, whisk together the melted butter and sugar until smooth and glossy. This forms the base of your batter.

Add Wet Ingredients: Incorporate the eggs one at a time, whisking well after each addition. Then stir in the milk and vanilla extract until everything is fully blended.

Combine Dry Ingredients: In a separate bowl, sift together the flour, baking soda, cinnamon, and salt. Sifting helps prevent clumps and evenly distributes the leavening agents.

Bring Mixtures Together: Gently fold the dry ingredients into the wet ingredients until just combined. The batter will be slightly thick—avoid overmixing to prevent a dense loaf.

Fold in Zucchini and Add-Ins: Using a spatula, gently fold in the grated zucchini and your chosen add-ins (nuts, raisins, or chocolate chips). Make sure the zucchini is well distributed throughout the batter.

Bake: Pour the batter into the prepared loaf pan and smooth the top with a spatula. Bake for 60–75 minutes. Check for doneness at 60 minutes by inserting a toothpick into the center; it should come out clean or with only a few moist crumbs.

Cool: Allow the bread to cool in the pan for 10 minutes before lifting it out with the parchment overhang. Transfer to a wire rack to cool completely. Slice once fully cooled.