Chocolate Zucchini Cupcakes

Peak zucchini season is from June to August, so now is a good time to get out your old trusty zucchini cake recipe - or your new one! Like the one I used for these chocolate zucchini cupcakes. If you're into luscious moist cake and rich chocolate buttercream, then I urge you to try it. This may be my favorite version of chocolate cupcakes, ever! (I know -with zucchini! Who would've guessed?).

You'll need a grater to shred the zucchini into little mulchy strands. A big box grater is ideal, but even the tiny one I used works well without much hassle. A whole 3 cups of shredded zucchini goes into the cake batter, and it virtually disappears into the cake as it bakes. You may occasionally see a little piece of green inside between bites, but they are few.

The chocolate buttercream frosting is lovely, too.  Six ounces of melted dark chocolate is added to cocoa buttercream, which makes the end result rich, but also light; a chocolate truffle-buttercream hybrid of the best sort.

I used a citrus zester to make zucchini peel toppers for the cupcakes. They don't contribute much flavor to the cupcake, especially when standing toe-to-toe with dark chocolate buttercream - but they look cute! Just wind a few of the strands around your index finger and slide them off, then place on top of the cupcakes.  If you choose to make them, add them just before you serve the cupcakes. The strands will dry out over time. They look and taste best fresh.

Confession: a zucchini cupcake with a tall glass of skim milk has been my lunch meal replacement for the past couple of days. It happens like this:

'I'll just have one bite.' 
'Oops! Cupcake for lunch.'

If you don't feel like scooping batter for 3 dozen cupcakes, then this recipe can be made as a single cake in a 13x9 baking dish with deep sides.

Chocolate Zucchini Cupcakes
Yields 3 1/2 dozen cupcakes or one 13x9 cake

1/2 cup (114 g) unsalted butter softened
1/2 cup (120 ml) canola or grapeseed oil
1 3/4 cups (345 g) sugar
1 teaspoon vanilla extract
1 teaspoon baking soda
1/2 teaspoon baking powder
1/2 teaspoon salt
2 large eggs
1/2 cup (113g) full fat sour cream
1/4 cup mayonnaise
2 1/2 cups (300 g) all-purpose Flour
3/4 cup unsweet cocoa powder
3 cups shredded organic zucchini (about 3 medium)

Dark chocolate buttercream
1 cup (228 g) unsalted butter, softened
1/4 teaspoon salt
4 cups (455 g) confectioners’ sugar
1/2 cup (45 g) unsweet cocoa powder
6 ounces dark chocolate, melted
Heavy cream, as needed

Preheat the oven to 325°F. Line a cupcake tin with paper liners (or two tins, if you have them).

Make the cupcakes: In the bowl of an electric mixer, combine the butter, oil, sugar, vanilla, baking soda, baking powder and salt. Beat in the eggs one at a time.

Add the sour cream, mayonnaise and cocoa powder. Stir in the flour. Beat until well combined. Fold in the zucchini with a rubber spatula.

Spoon the batter into the cupcake papers 3/4 full. Bake for 20-25 minutes, or until a toothpick tester comes out with a few moist crumbs clinging to it. The cupcakes will puff in the oven as they bake, but will sink slightly when removed from the oven (expect this). Remove the cupcakes from the pan and cool on a wire rack. Cool completely before frosting.

Make the frosting: In the bowl of an electric mixer with the whip attachment, beat together the butter and salt. Add the confectioners’ sugar and cocoa powder. Mix on low speed until just combined (the mixture may be crumbly at first – keep mixing!). Add the dark chocolate to the frosting and whip on high speed. Add heavy cream a little at a time until the mixture is piping consistency. You may need 1/4 cup or more depending on the cornstarch content of your confectioners’ sugar. Scrape down the bowl and whip again until light and fluffy.

Transfer the frosting to a piping bag fitted with a large French tip. Pipe the frosting onto the cupcakes.

Heather’s notes: I recommend using organic zucchini for this recipe since we use the entire vegetable (skin and all!) in this recipe.

Summer zucchini is usually bursting with juices, but occasionally you’ll run into a zucchini that’s dry and spongy when you grate it. it gives off little water which is not what we want for this recipe. If you get one like this, toss the zucchini in the compost pile (or feed the birds!) and start with a new one.

If making the 13x9-inch cake, increase the bake time to 30-35 minutes.

You’ll need an extra zucchini if you plan to make the garnish. Use a citrus zester – the kind with sharp holes (like this one) – to cut the zucchini skin into strands. To make the garnish, wind a few strands around your finger, slide them off and place on top of each cupcake. Do this just before serving so the strands are fresh and crisp.

link Chocolate Zucchini Cupcakes By Published: Chocolate Zucchini Cupcakes Recipe


  1. What???? Those look too delicious to be healthy!

  2. Haha... I SO know what you mean. There is has never been a time when I could finish just a bite of a cupcake. The entire thing always gets devoured! Love this recipe. Your pictures are gorgeous!

  3. Every time there is a version of chocolate zucchini cake around I'm reminded how it's probably the best type of chocolate cake out there. So moist and rich! These cupcakes look particularly divine :)

  4. The garnish is magnificent. So beautiful. Can't wait to dive into a mixing bowl of that luscious looking dark chocolate frosting. Dinner is served. Giggle.

  5. I have never imagine zucchini cupcakes, but definetly I will try it!


  6. Hello! Thank you for the recipe! Do you think I could Sunday the flour for a gluten free all purpose mix?

    1. Hi! Yes, I believe that would work well. I've had some experience baking with Bob's Red Mill 1 to 1 GF baking flour, and I think this flour (or a similar 1 to 1 flour) would be a fine substitution. I've not tried it with this recipe, but I see no reason why it wouldn't work!

      Thanks for your question!


  7. Heather! It worked! I replaced the all purpose with bobs red mill GF all purpose baking flour. I was nervous because I didn't have the 1 to 1 baking flour So I added about 3/4 tsp xanthan gum and I feel like they came out just like yours. I divided your recipe in half, used a 1/4 c ice cream scoop and had 13 cupcakes. Which was perfect for me so I could test one without anyone knowing. Thank you for the recipe!

  8. I have a question on your instructions.
    At what stage do I put the flour. Do I put it before the cocoa powder, or zucchini. It was not specified. I followed the instructions and as I was about to pour the mixture into the cupcake pans I saw the flour still on my counter and added it at the end. Hope it does not matter.

    1. Hi Bryant! Yes, it's perfectly fine to stir the flour in at the end. I'm so sorry I omitted that ingredient from the directions! I've added it back in. Thank you for letting me know.

  9. Hi! I’m planning on making these for my son’s 4th bday this weekend. With a marshmallow buttercream frosting fire and graham cracker crumble (he requested campfires!). Do you sweat your zucchini at all, or is the moisture important? I was thinking I might pre-shed the zucchini but I’m afraid they’ll throw off all of their water.


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