Preparation Steps

• Preheat the oven to 350°F (175°C). Grease a 9x5-inch loaf pan and line it with a strip of parchment, leaving a bit of overhang for easy removal.
• Whisk together the dry ingredients in a large bowl: flour, cocoa powder, baking soda, baking powder, salt, and instant espresso powder. Set aside so the baking powder and soda are evenly distributed.
• In a separate bowl, beat the eggs with both sugars until smooth and a little glossy (about 1 minute by hand). Add the oil and vanilla and whisk until fully incorporated.
• Pour the wet mixture into the dry ingredients and fold with a spatula just until most of the flour is moistened — avoid overmixing to keep the loaf tender.
• Stir the squeezed grated zucchini into the batter until evenly distributed. Fold in the chocolate chips and walnuts (if using). The batter will be thick and slightly glossy.
• Transfer the batter to the prepared loaf pan and smooth the top. Bake on the center rack for 50–60 minutes, checking at 50 minutes: a toothpick inserted in the center should come out with a few moist crumbs but not raw batter.
• Allow the loaf to cool in the pan for 10–12 minutes, then use the parchment overhang to lift it out and cool on a wire rack. Let it rest at least 30 minutes before slicing so the crumb sets.
• Store wrapped at room temperature for up to 3 days, or freeze slices for longer storage. Reheat gently before serving if desired.