Chocolate Zucchini Cake

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I love using zucchini to make cakes, quick breads, and muffins! Zucchini might be a surprising ingredient for dessert, but it’s the secret to this cake’s incredibly moist texture. If your garden has a surplus of zucchini, try this chocolate zucchini cake.

The cake is a moist and delicious dessert made in 1 layer, and it’s a breeze to prepare and bake from scratch. All you need is a mixer, a couple of zucchini, and a few pantry ingredients. Finish this moist, chocolatey zucchini cake with the fudgy chocolate frosting or use another favorite. The frosting is briefly cooked, then poured over the cooled cake. You can’t go wrong with this cake, as it’s a delightful treat!

What You’ll Like About This Recipe

• Exceptional moisture. The combination of butter, oil, buttermilk, and shredded zucchini ensures a plush, tender crumb that stays soft even after a day or two—no dry edges or crumbly slices.
• Deep chocolate flavor. Cocoa powder and a fudgy cooked frosting amplify the chocolate intensity, giving the cake a rich, satisfying depth without requiring melted chocolate in the batter.
• Effortless mixing. The batter comes together with straightforward steps and pantry staples, and the zucchini folds in easily without the need to squeeze or drain it.
• Feeds a crowd. Baked in a 9×13-inch pan, the cake slices neatly into generous servings, making it a dependable option for gatherings, potlucks, or bake-and-share moments.
• Versatile topping. The stovetop frosting pours on smoothly and sets quickly, creating a soft, fudge-like layer. It also adapts well to add-ins such as nuts, espresso powder, or even a pinch of sea salt.

Ingredient Notes

• Cocoa powder – Use natural unsweetened cocoa for the most predictable rise and classic chocolate flavor. Higher-quality cocoa will deepen the color and intensity.
• Butter and oil – Butter adds flavor, while oil ensures lasting moisture. Using both produces a tender crumb that stays soft for days.
• Buttermilk – Adds tang and acidity, helping the cake rise while improving texture. If needed, yogurt thinned with a little milk can work as a substitute.
• Zucchini – Finely shredded raw zucchini integrates seamlessly into the batter. No draining is required; the moisture helps create the cake’s signature texture.
• Flour – Standard all-purpose flour provides structure. Measure carefully or use grams for the most consistent results.
• Chocolate chips (for frosting) – Semisweet chips melt smoothly into the cooked sugar mixture, giving the frosting a glossy finish. Milk chocolate chips make a sweeter, creamier topping.

Steps to Make Chocolate Zucchini Cake

1. Prepare the baking pan and oven so the batter can go in immediately once mixed, preserving the rise from the leavening.
2. Whisk or sift together the dry ingredients to remove lumps from the cocoa powder and evenly distribute the baking soda and baking powder.
3. Cream the butter, oil, and sugar until smooth, which helps the sugar dissolve and creates a more even crumb once baked.
4. Add the dry ingredients and buttermilk in alternating portions to maintain a cohesive batter and avoid overmixing, which could toughen the cake.
5. Fold in the zucchini gently, letting it disappear into the batter without stirring excessively.
6. Bake the cake until the center springs back lightly and a tester comes out clean, then cool completely so the frosting sets properly.
7. Prepare the stovetop frosting just before pouring; the heat helps melt the chocolate chips and creates the signature soft-fudge texture as it cools on the cake.

Pro Tips

• Measure cocoa and flour with precision for the best texture; too much flour can make the cake dense.
• Fold the zucchini in at the end without squeezing out moisture—it’s essential for achieving the cake’s softness.
• Pour the frosting while hot so it spreads easily over the cooled cake and sets into a smooth, fudgy layer.
• Cool the cake completely before frosting; even slight warmth can cause the icing to absorb or become uneven.
• Store the cake covered at room temperature to maintain moisture and keep the frosting soft.

Recipe Variations

• Frosting: Top the cake with our cream cheese frosting, chocolate buttercream, or try this Irish cream frosting. These options pair wonderfully with chocolate desserts.
• Nuts: Fold in 1 cup of chopped pecans or walnuts along with the zucchini to add a crunchy texture.
• Garnish: Add sprinkles to the chocolate topping before it has a chance to harden for a festive touch.
• Spice: Add 1 teaspoon of cinnamon for a lightly Mexican chocolate flavor. This spice twist enhances the rich taste of chocolate zucchini cake.

How to Store

• Refrigerate only if necessary for longer storage, keeping the cake in an airtight container. The frosting will firm slightly in the fridge but softens again at room temperature.
• Freeze individual slices or the whole cake, tightly wrapped to prevent freezer burn. Thaw at room temperature and frost after thawing if you choose to freeze the cake unfrosted.
• Refresh by letting refrigerated or thawed slices sit at room temperature before serving to restore their soft, tender texture.