Chocolate Zucchini Cake

I’m not exaggerating when I say that this chocolate zucchini cake is the ultimate chocolate indulgence. Adding zucchini to a chocolate cake may seem a little strange but it not only absorbs all the rich chocolatey goodness it also adds a ton of moisture resulting in the most incredible soft, fudgy and delicious cake ever. Don’t worry, just like Carrot Cake or my Zucchini Bread recipe you can’t taste the vegetables at all it just adds moisture and a little added nutrition. During the summertime, it’s the perfect way to use up plentiful zucchini!

This cake is filled with chocolate chips and is covered in the most delicious chocolate buttercream frosting, yes triple chocolate! It’s also super easy to make and I have a ton of helpful tips to make sure this cake turns out perfectly.

What you need to make this recipe

All-purpose flour – all you need is regular all-purpose flour, don’t use other flours as they will likely be too fine.

Cocoa powder – use natural unsweetened cocoa powder and not Dutch process cocoa powder. Cocoa powder can dry cakes out so make sure to measure it properly by either weighing it with a kitchen scale or spooning it into your cup.

Espresso powder – this really helps bring out the chocolate flavor, the cake doesn’t taste of coffee. If you don’t have it you can leave it out but I highly recommend using it.

Baking soda & baking powder – I use a mix of both for extra lifting power.

Granulated sugar and brown sugar – I like to use both white and brown sugar to add flavor and moisture to the cake.

Eggs – eggs are important so the cake rises, make sure they are at room temperature before using.

Vegetable oil – this is used instead of butter to keep the cake nice and soft.

Sour cream – this also helps with moisture, you can swap it for plain yogurt if you don’t have any.

Vanilla – make sure to use vanilla extract and not essence, if you have it you can scrape the inside of a whole vanilla pod.

Zucchini – there are over 4 cups of shredded zucchini in this chocolate cake. Don’t worry you can’t taste or see it but it gives the cake the most delicious and decadent texture!

Chocolate chips – there’s enough sugar in this recipe so I recommend using semi-sweet or bitter-sweet chocolate for best results.

Butter – used to make the buttercream, make sure to use unsalted!

How to make Chocolate Zucchini Cake

1. Grate the zucchini into a bowl.

2. Mix the flour, cocoa powder, baking soda, baking powder, espresso powder (optional), and salt in a large bowl.

3. Combine the oil, sugars, eggs, sour cream, and vanilla together and mix it up to make sure everything is well incorporated.

4. Add the grated zucchini to the wet mixture and then give it a good mix.

5. Slowly pour the dry mixture in with the wet mixture and beat together on medium speed. Add in the chocolate chips then pour the batter into the buttered pans. Bake then let them cool.

6. For the Chocolate buttercream; melt the chocolate chips with the cream then set aside to cool. Cream the butter in a stand mixer then sift in the cocoa powder. Beat in the powdered sugar slowly to be sure you get the proper consistency, then add the cream. You may now add the vanilla and melted and cooled chocolate. Continue mixing until you have a nice and fluffy, even consistency.

7. Pipe the chocolate buttercream onto your first layer and repeat this step until your cake is fully stacked. Give the whole cake a final coat all around with the chocolate buttercream and smooth it out with a bench scraper and an offset spatula.

8. Pipe dollops of buttercream around the top edge of your cake if desired then serve.

Top tips for making this recipe

• Make sure to measure your flour correctly Adding too much flour to the recipe is the most common mistake. The best and easiest way to measure flour is by using a kitchen scale. If you don’t have one then fluff your flour with a spoon, sprinkle it into your measuring cup, and use a knife to level it off.
• Use three 8 inch cake pans so each layer is high and uniformed.
• Make sure to prepare your cake pans, grease them in butter then place a round piece of parchment paper at the bottom of each pan. Finally, dust them in cocoa powder removing any excess. This will make sure that your cake won’t stick and will give you an easy release.
• The zucchini grates really easily and quickly using the big holes on a box grater. You can use a food processor if you don’t have one.
• If the zucchini seems extra wet squeeze out any excess moisture.
• Make sure your refrigerated ingredients are at room temperature before starting especially the eggs!
• To test that the cake is ready insert a small skewer or toothpick into the center of the cake, if it comes out clean it’s ready.
• To get uniform flat layers that are moist inside and out try using cake strips! You can buy a set on the shop page or make your own from foil and paper towels at home.
• Make sure the cake is cooled completely before frosting.
• Your butter should be softened at room temperature before making the buttercream or it’ll be lumpy and unpleasant.
• Instead of Chocolate Buttercream, you could use Mocha Frosting, Cream Cheese Frosting, or Swiss Meringue Buttercream instead.
• An offset spatula makes spreading the frosting super easy.
• I like to use a star tip to pipe some frosting around the top edge of the cake. I used an 869 tip but any larger star tip will work well.
• You can use the batter to make cupcakes instead of a whole cake.

Frequently Asked Questions

Can I prepare this in advance?

Yes, you can prepare the buttercream and chocolate zucchini cake 1-2 days in advance and store them separately before assembling. Make sure to refrigerate the buttercream.

Do I need to peel the zucchini first?

Peeling is not needed and you will not taste or feel the peel in the cake. If you’re trying to sneak this in and have it be completely invisible then peeling will eliminate any chance a picky eater will see what’s inside.

How long does it last?

Leftovers will keep well at room temperature or stored in the fridge for 4-5 days. Make sure to cover it with plastic wrap if possible to stop it from drying out.

Can it be frozen?

Yes, you can freeze the chocolate zucchini cake for up to 3 months. Wrap it well in plastic wrap and foil and defrost overnight in the refrigerator. 

If you’ve tried this Chocolate Zucchini Cake recipe then don’t forget to leave a rating and let me know how you got on in the comments below, I love hearing from you!