Chocolate Zucchini Cake

Whisking Wolf
by Whisking Wolf
12 slices
1 hr 5 min

Just when you think chocolate cake couldn’t get any better, Chocolate Cake + Zucchini adds another level of deliciousness. Packed with moisture-rich zucchini, this heavenly cake is frosted with a thick layer of chocolate buttercream and bakes up perfectly every time.

My ancestry test results are finally in. Instead of descending from England, France or Spain, it turns out I descended from eggs, flour and sugar. Basically, cake is in my DNA. And while normal family trees have foliage, mine has frosting. Whipped cream, buttercream, cream cheese, I come from a diverse background of frosted deliciousness. Cake is at the core of who I am, yet my son despises it. I’ve always been suspicious of the child, but this screams switched at birth.

I should return him for a refund. Sure, it’s been fifteen years but if Nordstrom has a no-questions-asked return policy then so should his baby hospital. There’s no way my flesh and blood can hate cake; it’s not genetically possible. Not to mention it’s just plain weird. How can a kid of mine not love a big slice of cake? It boggles my mind.

As much as my son’s anti-cake stance tortures my soul, I’m making peace with it today. If he doesn’t want to eat my favorite dessert then fine, it’s more Chocolate Zucchini cake for me. My glass isn’t half empty, it’s half full: of lactose-free milk. Trust me, a tall, cold glass of milk is the perfect accompaniment for this perfect chocolate cake. Made with simple ingredients and moisture-rich zucchini, each slice is frosted with a thick layer of chocolate buttercream. It is heaven on a fork (for anyone but my finicky son).

Before sharing the recipe for Chocolate Cake Zucchini here are a few tips and tricks to help you out:

Ingredient Tips and Tricks

Always use the spoon and level method to measure flour. Scooping flour is a no-no. That technique overpacks flour into the measuring cup which results in a drier, denser cake than the moist, tender cake you get from properly measured flour.

For best results be sure all ingredients (butter, eggs and yes, even sour cream) are at room temperature before beginning.

Espresso powder is a secret ingredient that enhances the chocolate flavor. For best results, don’t skip this ingredient!

Preparation Tips and Tricks

Cool cake completely before frosting with buttercream.

Grate zucchini with the large holes on a box grater. Three cups of grated zucchini is approximately two medium zucchini.

Storage and Freezing Tips for Chocolate Cake + Zucchini

Cover and store cake at room temperature up to 3 days or in the refrigerator up to 5 days.

Frosted cake can be frozen up to 3 months. First cover with plastic wrap then with a layer of aluminum foil and place in an airtight container before freezing. Thaw overnight in the refrigerator then bring to room temperature before serving.

I hope you enjoy this recipe for Chocolate Cake + Zucchini. Please leave a comment and a rating at the bottom of this blog when you try it for yourself. And, while you’re at it, sign up for my Recipe Newsletter so you never miss a tempting recipe.

Finally, if you like baking with zucchini then you’ll love this recipe for Chocolate Chip Zucchini Bread. Loaded with moisture and studded with dark chocolate chips, this quick bread gets an extra layer of flavor from chocolate ganache frosting.

Recipe details
  • 12  slices
  • Prep time: 20 Minutes Cook time: 45 Minutes Total time: 1 hr 5 min
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Chocolate Cake
  • 2 1/4 cups all-purpose flour unbleached
  • 3/4 cup unsweetened cocoa powder
  • 1 tsp baking soda
  • 1/2 tsp baking powder
  • 1/2 tsp sea salt fine
  • 1 tsp espresso powder
  • 1 cup olive oil
  • 1 cup granulated sugar
  • 3/4 cup light brown sugar packed
  • 4 large eggs room temperature
  • 1/2 cup sour cream room temperature
  • 2 tsp vanilla extract pure
  • 3 cups shredded zucchini
  • 1 cup chocolate chips
Chocolate Frosting
  • 1 1/2 cups unsalted butter room temperature
  • 3 1/2 cups powdered sugar
  • 3/4 cup unsweetened cocoa powder
  • 2 tsp vanilla extract pure
  • 1/4 cup heavy cream room temperature
  • 1/8 tsp sea salt fine
  • 1/4 cup chopped chocolate
Chocolate Cake
Preheat oven to 350 degrees. Coat a 9 x 13 metal baking pan with nonstick spray. Set aside.
In a large mixing bowl, sift together dry ingredients: flour, cocoa powder, baking soda. baking powder, salt and espresso powder. Set aside.
In a separate bowl, use an electric mixer to beat together oil and both sugars.
Add eggs, one at a time, beating after each addition until well incorporated.
Beat in sour cream, vanilla and grated zucchini until combined.
Gradually add dry ingredients to wet, beating on medium speed until just combined. Do not overmix.
Add chocolate chips, stirring with a wooden spoon until evenly distributed.
Pour batter into prepared baking pan and bake for 45 minutes. Cake is done when a tester inserted into the center comes out clean.
Place baking pan on a wire rack to cool completely, approximately 2 hours, before frosting with chocolate buttercream.
Chocolate Frosting
Beat butter with an electric mixer on medium speed until creamy and smooth, approximately 2 minutes. Scrape down the sides of the bowl with a spatula as needed.
Add powdered sugar, cocoa powder, vanilla, heavy cream and salt beating on low until incorporated then increase speed to high and beat until fluffy, approximately 2 minutes.
Assembly and Storage
Frost cake with buttercream then top with chopped chocolate if desired.
For pristine slices, clean knife blade with hot water in between cuts.
Cake will keep covered at room temperature up to 3 days or refrigerated up to 5 days.
Whisking Wolf
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  • Mary Novinger-Ulring Mary Novinger-Ulring on Jul 14, 2021

    Do you squeeze out the excess water from the zucchini's?

    • Whisking Wolf Whisking Wolf on Jul 14, 2021

      Hi Mary,

      I like to keep all the moisture from the shredded zucchini so there's no need to squeeze or pat dry. Thanks for the question!

  • Sandra Sandra on Jul 18, 2021

    You had me absolutely laughing out loud at your comments about needing to return your weird kid. I am a cake-a-holic myself and couldn't imagine a day without a slice of it slipped in somewhere! I would never ever have thought of adding zucchini to chocolate but your pictures look great so am tempted to try it :-)

    • Whisking Wolf Whisking Wolf on Jul 18, 2021

      Hi Sandra,

      I'm glad you had a good laugh, hearing this made my day. Cake is like kryptonite so it's hard to wrap my head around someone not liking it--espececially when that someone is my son lol. Hope you get a chance to try the recipe, it really is crazy good.