This Sourdough Chocolate Zucchini Cake is light and fluffy, moist, and a decadent chocolate treat. It's topped with a chocolate buttercream frosting, and using zucchini in the cake batter makes it extra moist! It's a beautiful single-layer cake that is perfect for a dessert or a special occasion.
Why you'll love this recipe
- This cake is great way to use up some of your summer zucchini to make a delicious dessert!
- Looking for more zucchini recipes? You might like these Chocolate Sourdough Zucchini Muffins and this Sourdough Zucchini Bread.
- This recipe uses sourdough discard, but could easily be modified to use active sourdough starter, if you prefer.
- You can add chocolate chips to the batter if you'd like a bit of extra chocolate!
- This cake is topped with a chocolate buttercream frosting, perfect for all chocolate lovers!
- If you'd like a non-chocolate zucchini cake, try this Sourdough Zucchini Cake!
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Ingredients
There are only a few key ingredients you'll need to bring this recipe together.
- Unsweetened cocoa powder: This is where the cake gets its chocolately flavor!
- Sourdough discard: The sourdough discard should be unfed and at room temperature for this recipe. This recipe is designed for a sourdough starter with a 1:1 ratio (when you feed your starter, it's with 1 part flour and 1 part water). If your starter uses a different ratio, you may need to adjust some of the ingredients in this recipe.
- Learn more about how to make a sourdough starter.
- Zucchini: The zucchini should be shredded (on the large holes of a box grater), and lightly drained for this recipe. You don't need to remove all moisture, just some.
- You might also like these Sourdough Zucchini Waffles!
See full recipe below for detailed directions.
Substitutions & Variations
This is a very adaptable recipe and below are a few easy substitutions and variations you can try.
- Use active sourdough starter - While it's not needed for leavening purposes, if you'd like to use active sourdough starter for this recipe, you can. To do so, replace the sourdough discard with active starter (200g). You will not need to change any other ingredients in the recipe.
- Use yellow summer squash - Yellow summer squash and zucchini are interchangeable in this recipe. You can make it with either one (or a mix)!
- Add chocolate chips - Add 1 cup of chocolate chips to the batter for an extra chocolate kick!
I have not tested this recipe with other variations, but if you do, let us know how it turns out in the comments! I always love to hear how you're adapting these recipes and use those as ideas for future recipes as well!
How to Make Sourdough Chocolate Zucchini Cake
This cake comes together in a few simple steps. The full recipe with detailed directions is at the bottom of this post.
- Step 1: Mix together the dry ingredients (minus the sugars).
- Step 2: Shred and lightly drain your zucchini. You don't need to remove all liquid, just some!
- Step 3: Mix together the sugars and wet ingredients.
- Step 4: Fold in the shredded zucchini. and stir until combined.
- Step 5: Stir until combined. Transfer the batter to a greased and lined 9-inch springform pan. Bake until a toothpick inserted in the center comes out clean.
- Step 6: Let the cake cool completely, then top with the frosting. Slice and serve.
Expert Baking Tips
- Shred and drain the zucchini. You do not need to remove all moisture, but some. I like to do this by pressing the shredded zucchini between layers of paper towels, or wrapping the shredded zucchini in paper towels and wringing it out over the sink.
- Use a springform pan. This recipe will not work in a regular 9-inch cake pan (it will be too tall). Make sure to use a 9-inch springform pan.
- Let the cake cool completely before frosting. If the cake is even slightly warm, the frosting will begin to melt.
- When you do make the frosting, ice the cake right away. The buttercream will stiffen slightly as it sits, which makes it harder to spread evenly. Spread the frosting on the cake as soon as you have it ready!
- Cut the cake with a serrated knife for extra-clean cuts!
- Looking for other summer cakes? Try this Sourdough Fig Cake!
Storage
Room Temperature Storage: Store this chocolate cake covered at room temperature for up to 3 days. Keep in mind that the "cut" side of the cake will dry out first. You can place a piece of plastic wrap on that side of the cake to try to prevent drying.
Freezer Storage: You can freeze the entire cake either before or after frosting.
- Thawing frozen cake: When ready to serve, let the cake thaw in the fridge overnight or at room temperature for a few hours. Then, slice and serve.
- To freeze before frosting: Let the cake cool fully, then wrap the cake in plastic wrap, followed by aluminum foil (or a freezer-safe bag). Freeze for up to 3 months. You will frost the cake after thawing when you are ready to serve.
- To freeze after frosting: Freeze the full, frosted cake on a plate or baking sheet for about 60 minutes to set the frosting. Then, cut the cake into pieces (as you like, or leave the cake whole) and wrap the cake in plastic wrap, then aluminum foil (or a freezer-safe bag). Freeze for up to 3 months.
Recipe FAQs
Can I make this cake in a 9-inch round cake pan?
This recipe is designed for a 9-inch round springform pan. It will be too much volume for a regular cake pan.
More Sourdough Discard Zucchini Recipes
If you tried this Sourdough Chocolate Zucchini Cake or any other recipe on my website, please leave a ⭐ star rating and let me know how it went in the comments below. I'd love to hear from you! Happy Baking!
Sourdough Chocolate Zucchini Cake
A decadent recipe for Sourdough Chocolate Zucchini Cake topped with a chocolate buttercream frosting. Perfect for dessert or a special occasion, and packed with zucchini (and you'd never know it!)
Ingredients
For the Cake
- 1 ¼ cup all-purpose flour
- ½ cup unsweetened cocoa powder
- 1 ½ teaspoons baking powder
- ½ teaspoon baking soda
- 1 teapsoon espresso powder
- ½ teaspoon kosher salt
- ½ cup vegetable oil or other neutral oil
- ½ cup granulated sugar
- ½ cup light brown sugar packed
- 200 grams (about ¾ cup) sourdough discard unfed, at room temperature
- 2 eggs room temperature
- 2 teaspoons vanilla extract
- 1 ½ cups zucchini shredded and drained
- 1 cup chocolate chips optional
For the Frosting
- ½ cup unsalted butter softened
- 1 ¾ cups confectioner's sugar
- ⅓ cup cocoa powder
- 2-3 Tablespoons milk non-dairy or regular dairy
- 1 teaspoon vanilla extract
- Pinch of salt
Instructions
- Preheat the oven to 350℉. Grease and line a 9-inch springform pan with parchment paper. Set aside.
- In a medium bowl, whisk together the flour, cocoa powder, baking powder, baking soda, espresso powder, and salt.
- Shred the zucchini on the large holes of a box grater, then drain slightly (you don't need to remove all liquid, just some). To drain, press the shredded zucchini between layers of paper towels. Set aside.
- In a large bowl, whisk together the vegetable oil, granulated sugar, brown sugar, sourdough discard, eggs, and vanilla extract until combined. Fold in the shredded zucchini (and chocolate chips, if using).
- Fold the dry ingredients into the wet ingredients, mixing until nearly combined. Fold in the zucchini and mix until combined. The batter should be somewhat thick.
- Transfer the batter to the prepared baking pan, making sure to spread it evenly. Bake for 45-50 minutes, or until a toothpick inserted in the center comes out clean. Let the cake cool in the pan, then remove the ring and transfer to a cooling rack to cool fully before icing.
- To make the icing, use a hand-held mixer to cream the butter in a medium-sized bowl until light and fluffy, 1-2 minutes. Slowly add the confectioner's sugar and cocoa powder, mixing until combined. Add the vanilla extract and 2 Tablespoons of milk, mixing until a smooth icing forms. Add more milk only if needed (the icing should be thick, but spreadable).
- Spread the icing on the cooled cake, then slice and serve.
Video
Notes
To make this recipe with active sourdough starter, replace the sourdough discard with active starter (200g). You do not ned to make any other changes to the recipe.
If you're looking for a non-chocolate zucchini cake option, try my Sourdough Zucchini Cake!
Nutrition
Calories: 288kcalCarbohydrates: 47gProtein: 3gFat: 17gSaturated Fat: 7gPolyunsaturated Fat: 4gMonounsaturated Fat: 3gTrans Fat: 0.3gCholesterol: 36mgSodium: 160mgPotassium: 166mgFiber: 2gSugar: 20gVitamin A: 233IUVitamin C: 2mgCalcium: 52mgIron: 1mg
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Katie G says
Amazing recipe! I omitted the chocolate chips and only did 100g of sourdough discard since that’s all I had at the time. I also baked it in a regular 9 inch cake pan and it turned out great!
Will be making again.
Jessica Vogl says
I made this cake SEVERAL times in one week, and it is absolutely delicious! Moist and decadent and hard to resist!