Chocolate Zucchini Loaf Cake with Chocolate Icing is rich, moist, and full of deep chocolate flavor; no one will ever guess it’s packed with zucchini. The shiny, sweet chocolate icing takes it from a simple loaf cake to a bakery-style treat.
The zucchini keeps the crumb incredibly soft without making the cake taste like vegetables. It’s the perfect way to sneak a little produce into a dessert everyone will love.
This snack cake is perfect for summer and early fall when fresh zucchini is in abundance. It’s also great year-round as a comforting bake to enjoy with coffee or tea.
Bring it to brunches, potlucks, or wrap it up for a sweet homemade gift. Serve it as an after-school snack, a casual dessert, or even slightly warm with ice cream for something extra special.
If you loved this loaf cake, try my Zucchini Brownies for another fudgy chocolate treat. You’d also enjoy my Zucchini Spice Snack Cake with Cinnamon Maple Buttercream for a cozy, spiced version.
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Ingredients
For the Cake
All-purpose flour
Unsweetened cocoa powder
Baking soda
Baking powder
Kosher salt
Espresso powder (optional)
Brown sugar
Neutral oil
Eggs
Vanilla extract
Whole milk or buttermilk
Grated zucchini
Mini chocolate chips (optional)
For the Chocolate Icing
Unsalted butter
Unsweetened cocoa powder
Powdered sugar
Boiling water
Vanilla extract
See recipe card for quantities.
Instructions
This recipe is easy to make—just a few simple steps and no mixer required for the batter.
Step 1: Mix the batter: Combine wet ingredients, then fold in zucchini and dry mix.
Step 2: Bake the loaf: Pour into a lined 8x4 loaf pan and bake at 350°F until done.
Step 3: Make the icing: Whisk cocoa, boiling water, butter, vanilla, and powdered sugar until glossy.
Step 4: Ice & serve: Spread icing over the cooled loaf and let it set before slicing.
Hint: Weighing your ingredients with a kitchen scale is the easiest way to guarantee accuracy, giving you perfect texture and consistent results every time you bake.
Substitutions
Need to make a few swaps? Here are some easy options:
- Oil for Butter in the Icing: You can use melted butter substitute or a neutral oil, but butter gives the icing the best flavor.
- Buttermilk or Milk: Either works in the cake—if you don’t have buttermilk, regular whole milk keeps it just as moist.
- Brown Sugar: Swap for granulated sugar if needed, though brown sugar adds extra richness and moisture.
- Espresso Powder: Optional, but if you don’t have it, simply leave it out—the cake will still be deeply chocolatey.
- Chocolate Chips: Use chopped chocolate bars or omit them entirely for a smoother loaf.
- Gluten-Free: A 1:1 gluten-free flour blend works well; the texture will be slightly softer but still delicious.
Variations
Want to change it up? Try one of these ideas:
- Double Chocolate Zucchini Loaf: Add extra chocolate chips to the batter for even more gooey chocolate pockets.
- Nutty Chocolate Loaf: Fold in chopped walnuts or pecans for crunch.
- Glazed Instead of Iced: Skip the thick icing and drizzle with a simple powdered sugar glaze for a lighter finish.
- Mini Loaves or Muffins: Bake the batter in mini loaf pans or muffin tins for grab-and-go treats.
Equipment
- Kitchen scale
- loaf pan (I used a 1.5-pound loaf pan in the pictures, but a 1-pound or 1.25-pound pan should work well too)
- Parchment paper
- Mixing bowls (medium and large)
- Whisk
- Spatula or wooden spoon
- Measuring spoons
- Grater (for zucchini)
- Wire rack (for cooling)
- Toothpick or cake tester
- Small offset spatula or spoon (for spreading icing)
Storage
Store the cake in an airtight container at room temperature for up to 3 days, or refrigerate for up to 5 days.
You can also freeze it—wrap slices individually in plastic wrap and aluminum foil or the whole loaf tightly and freeze for up to 2 months. Thaw at in the refrigerator before moving to room temperature (to minimize condensation) and enjoy as-is or warm slightly before serving.
Audrey's tip
For the best texture, don’t squeeze the zucchini before adding it to the batter—the natural moisture keeps the cake extra soft and fudgy. And for a shiny, smooth icing, sift your cocoa powder and powdered sugar before mixing to avoid any lumps.
Related
Looking for other recipes like this? Try these:
Chocolate Zucchini Loaf Cake With Fudgy Chocolate Icing
Equipment
- 8x4-inch loaf pan
- Parchment Paper
- Mixing bowls (medium and large)
- Whisk
- Spatula or wooden spoon
- Measuring cups and spoons (or a kitchen scale for accuracy)
- Grater (for zucchini)
- Wire rack (for cooling)
- Toothpick or cake tester
- Small offset spatula or spoon (for spreading icing)
Ingredients
For the cake:
- 210 g all-purpose flour 1 ¾ cups
- 45 g unsweetened cocoa powder ½ cup
- 1 teaspoon baking soda
- ½ teaspoon baking powder
- ½ teaspoon kosher salt
- 1 teaspoon espresso powder optional, enhances chocolate flavor
- 200 g brown sugar 1 cup, packed
- 120 ml neutral oil ½ cup
- 2 large eggs
- 1 teaspoon vanilla extract
- 120 ml whole milk or buttermilk ½ cup
- 260 g grated zucchini about 2 cups, loosely packed
- 85 g mini chocolate chips ½ cup, optional
For the chocolate icing:
- 90 g unsalted butter ¼ cup or ½ stick
- 40 g unsweetened cocoa powder ½ cup
- 360 g powdered sugar 3 cups
- 6 tablespoon boiling water
- 2 teaspoon vanilla extract
Instructions
- Prep the pan: Preheat oven to 350°F (175°C). Grease and line an 8x4-inch loaf pan with parchment paper.
- Mix the dry ingredients: In a medium bowl, whisk together the flour, cocoa powder, baking soda, baking powder, salt, and espresso powder.
- Make the batter: In a large bowl, whisk together the brown sugar, oil, eggs, vanilla, and milk until smooth and emulsified.
- Fold in zucchini: Stir in the grated zucchini and chocolate chips (if using) until evenly distributed.
- Combine & bake: Add the dry ingredients to the wet and fold gently until just combined. Pour the batter into the prepared pan and smooth the top. Bake for 45–55 minutes, or until a toothpick inserted in the center comes out with just a few moist crumbs.
- Cool the cake: Let the loaf cool in the pan for 10–15 minutes, then transfer to a wire rack to cool completely.
- Make the chocolate icing: In a medium bowl, whisk together the boiling water and cocoa powder until smooth. Add the softened butter and vanilla, then beat in the powdered sugar gradually until smooth and glossy. The icing should be thick but pourable—add a splash more water if needed.
- Ice the cake: Once the cake is fully cool, spread the icing generously over the top and let it set for 15–20 minutes before slicing.
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