Double Chocolate Zucchini Cake

This rich, one-bowl Double Chocolate Zucchini Cake is the kind of moist cake you’ll want on repeat all summer and fall. Packed with three cups of zucchini, dark chocolate chips, and baked into a classic bundt cake, it’s one of those old-school desserts that never goes out of style. Whether you glaze it or leave it plain, the deep chocolate flavor and tender crumb make it a crowd-pleasing treat. And best of all? It uses just one large mixing bowl and a handful of pantry staples.

I came up with this recipe during one of those peak zucchini season moments—you know the ones, where garden baskets are overflowing. It’s become one of my favorite ways to use an abundance of zucchini without anyone asking if there are veggies in their cake. With a thick chocolate glaze poured over the top, this cake turns into a decadent dessert that’s perfect for after dinner or special gatherings.

If you’re looking for more zucchini recipes, try my savory Cheesy Zucchini Egg Casserole for breakfast/brunch (no bread) or my Cast Iron Zucchini Tomato Bake for something tasty.

Why You’ll Love This Chocolate Zucchini Cake

One-bowl mixing: Use a large bowl to bring everything together.

Double chocolate goodness: Unsweetened cocoa powder and dark chocolate chips for intense chocolate flavor.

3 Cups Of Veggies:  Perfect way to use garden bounty or that oversized zucchini your neighbor just ‘gifted’ you. You know the one I am talking about, right? (Remove seeds if using the gigantic zucchini they gave you, and grate just the flesh and skin of the zucchini.)

Canadian Baking Culture Meets Garden Abundance

Chocolate cake has long been a staple on Canadian tables, particularly in rural communities where home baking is a common practice. Recipes featuring zucchini began appearing in Canadian cookbooks by the late 1960s and early 1970s, coinciding with the back-to-the-land movement and a growing interest in home gardening. As someone born to back-to-the-land hippie parents living off-grid, I can attest—zucchini was never in short supply. We knew the value of a good “garden cake” before it became trendy. 

Community and church cookbooks from the Prairies and Ontario often included zucchini loaves and cakes, sometimes humorously marketed as “garden surprise” desserts. These recipes offered a way to utilize abundant summer produce while creating a delicious cake with a moist texture and added moisture.

Zucchini grows exceptionally well in Canadian soil, and if you’ve ever grown it, you know—you blink and suddenly you’ve got too many. That’s where recipes like this chocolate zucchini cake recipe come in. It turns what might feel like a surplus into a delicious cake worth sharing.

How To Make This Double Chocolate Zucchini Bundt Cake

Preheat your oven to 350°F. While it’s heating, grease and flour your bundt pan thoroughly—be sure to get into the grooves and around the center cone. This helps your cake batter release cleanly and ensures the top of the cake looks picture-perfect.

Wash and grate the zucchini (no need to peel it). I used about two whole medium-sized zucchini for a full three cups of shredded zucchini. You can also grate to a finer texture which will be less noticeable when eating the cake, it’s a matter of personal preference. Set the grated zucchini aside.

In a large mixing bowl, whisk together all the dry ingredients. That includes the flour, baking powder, baking soda, salt, cinnamon, cloves, and unsweetened cocoa powder.

Make a well in the center and add your wet ingredients: vegetable oil, eggs, and brown sugar. Stir until mostly combined. See note below.

Note: You can mix this cake entirely with a regular table fork. Start in the center of the well and in circles beat the egg into the oil and work in continuously larger circles until you’ve drawn as much of the dry ingredients into the wet as possible.

Now fold in the grated zucchini and mix until fully incorporated, as the batter relies on the extra moisture from the zucchini. The batter will appear thick when compared to a white cake batter, and that’s okay. Next, add in the dark chocolate chips and walnuts (if using). 

Again, this batter is extremely thick, so pouring needs to be done carefully, as it tends to come out all at once. Spoon it into the pan for the safest option. Once the batter is in your prepared pan, you can smooth the top level.

This cake has a long bake time of  1 hour and 20-30 minutes. Be sure to place the unbaked cake on in the center of the oven as you would for other baked goods. You’ll know it’s done when a cake tester comes out with just a few moist crumbs. Be cautious of melted chocolate clinging to the tester—it doesn’t mean it’s underbaked. It’s pretty safe to test this cake multiple times without worrying about it falling. 

Cool the chocolate cake in the bundt pan for 15 minutes. Then invert the cake onto the baking rack and carefully lift it off. Be sure to allow the cake to cool completely before adding your glaze, or it will run right off, especially if you thin it out too much.

To make the fudgy chocolate coating/glaze, you will need a small bowl. Whisk together in the bowl the melted butter, confectioners’ sugar, cream, golden corn syrup, cocoa powder, and vanilla extract until smooth. 

Pour or spoon the chocolate glaze generously around the top of the cake, allowing it to slowly drip over and down the sides. If you find it’s too thick for your liking before adding it to the cake, add just a tad (1/4 tsp at a time) more cream until you achieve the desired thickness or rather thinness. The glaze will set with a glossy finish with a rich fudgy texture that complements the cake perfectly.

Ingredients:

Note to my Canadian readers: You’re not alone if you’re sourcing these ingredients without relying on U.S.-based imports. Given our country’s current challenges, supporting Canadian-owned businesses and Canadian-made products matters more than ever. Every little bit helps keep our food systems strong, our neighbors employed, and our dollars in our communities.

You will now find more Canadian content on the blog as I continue to source Canadian food brands and products. 

And to our American friends—we still love you! We always have and will. But when possible, we’re leaning toward local to keep our shelves stocked and our people supported.

All-purpose flour: Gives the chocolate cake its structure and classic dense crumb. Okay, I know I’ve said it once or twice before, but Five Roses Flour has been a big part of my baking history, so I can’t shout it out enough that this flour brand is the BEST hands down. 

Baking powder: Helps the cake rise for a softer bite. 

Baking soda: Is activated with the acidic ingredients (like brown sugar, which has molasses) to create a faster rise. Think of it as the superwoman of the recipe, giving the batter its initial lift, while baking powder comes along to finish the job and support the structure as it bakes.

Salt – Balances sweetness and deepens the chocolate notes.

Cinnamon – Adds a warm undertone that complements the chocolate.

Cloves – A hint of earthy spice that adds depth to the flavor profile.

Unsweetened natural cocoa powder – Brings out that intense chocolate flavor in every bite. There’s a bit of debate in our home as to who makes the better cocoa powder. I am a staunch supporter and user of Fry’s Cocoa Powder. 

Vegetable oil – This neutral-flavored ingredient keeps the cake moist and soft for days.

Brown sugar – Adds rich sweetness and helps retain moisture in the crumb. I used dark brown sugar from Lantic Rogers.

Large eggs – Bind the ingredients and create structure for slicing.

Shredded zucchini – Adds subtle sweetness and keeps the cake ultra moist. 

Dark chocolate chips – Melt into delicious pockets for that double chocolate experience.

Walnuts (optional) – Add a crunchy, nutty layer to contrast with the soft cake.

Melted butter – Provides a rich, velvety base that carries the cocoa and smooths the glaze. Gay Lea butter worked great in this chocolate glaze.

Confectioners’ sugar – Sweetens the glaze and gives it that classic silky finish. Also made by  Lantic Rogers.

Cream – Adds body and creaminess for a pourable, luscious texture. Nielsen Dairy has great milk and cream products. 

Golden corn syrup – Gives the glaze a glossy finish and helps it set without cracking.

Unsweetened cocoa powder – Deepens the chocolate flavor and balances the sweetness. 

Vanilla extract – Enhances and rounds out the zucchini chocolate flavor with a warm, fragrant finish.

Substitutions and Add-Ins For This Double Chocolate Zucchini Bundt Cake.

All-purpose flour: Swap with cake flour for a lighter crumb or oat flour for a rustic texture.

Baking powder: Use ¼ teaspoon baking soda plus ½ teaspoon lemon juice or vinegar per teaspoon. Note: If replacing either baking soda or powder, it’s best to only replace one or the other, not both.

Baking soda – Replace with 1 tsp baking powder per ¼ tsp (note: cake will be slightly denser).

Salt :– Remains-

Cinnamon: Try nutmeg or cardamom for a warmer spiced profile.

Cloves: Add ½ tsp allspice or more cinnamon for a similar earthy note.

Unsweetened cocoa powder: Use Dutch-processed cocoa for deeper color and flavor.

Vegetable oil: Swap with canola or melted coconut oil for different neutral bases.

Brown sugar: Use white sugar (note the cake will only be sweetened while brown sugar also provides moisture, deeper flavor and tender texture), maple sugar (an expensive alternative for a humble baked good. I would only replace part of the brown with one cup of the maple sugar as maple has a very distinct flavor.), or coconut sugar depending on flavor preferences. 

Large eggs: Sub with flax eggs if you prefer.

Shredded zucchini: Use grated yellow squash or carrot for a similar moisture boost.

Dark chocolate chips: Try semi-sweet chips, milk chocolate chips, or chopped dark chocolate chunks.

Walnuts: Replace with pecans, almonds, or omit entirely for a nut-free option.

This bundt cake batter can also be divided between loaf pans and baked that way. Just be sure to use a prepared pan when baking. If you’re not in the mood for bundt cake or loaf cake, this chocolate zucchini cake batter also makes excellent chocolate zucchini muffins.

Expert Tips, Serving and Storing Suggestions For This Double Chocolate Zucchini Bundt Cake:

Tip #1: Grease and flour the pan. Even with a nonstick bundt pan, it’s essential to grease and flour all the grooves—including the center cone. This helps the cake release cleanly and preserves the shape. I did it for this cake, and it fell right out when I tipped it over.

Tip #2: Don’t skip the zucchini. The grated zucchini adds crucial moisture, creating a soft and tender crumb. You won’t taste it—but you’ll miss it if it’s gone.

Tip #3: Watch the chocolate chips. Melted chocolate can stick to your tester. To check doneness, insert a toothpick in a non-chip section and look for a few moist crumbs—not raw batter.

This delicious cake is best served in thick slices with a glass of cold milk or a strong cup of coffee. Not adding the chocolate glaze, but want a bit of extra decadence? Top a thick slice with freshly made sweetened whipped cream or a scoop of your favorite vanilla ice cream. 

The glossy, thick glaze makes it feel elegant enough for dinner parties, but it’s also a great way to round out a weekend brunch or school lunchbox treat. I’ve even packed slices of this moist cake for road trips and potlucks—it’s sturdy, not crumbly, and just sweet enough.

To store, keep the thoroughly cooled chocolate zucchini cake covered at room temperature for up to 5 days. It stays fresh and holds its moist texture when wrapped tightly or stored in an airtight container. If you prefer a chilled cake, you can refrigerate it—but make sure it’s well-covered to prevent it from drying out. For more extended storage, slice and freeze individual pieces so you can grab a ready-made dessert or school snack anytime. Just thaw at room temperature and enjoy a slice of this rich, chocolatey baked good when the craving hits.

If you make this double chocolate zucchini bundt cake, I’d love to hear how it turned out! Leave a comment or rating below—your feedback helps others find and fall in love with this recipe too.