This Sourdough Chocolate Zucchini Bread is a rich, chocolatey treat made with sourdough discard, fresh zucchini, and plenty of chocolate chips. Easy to make and ready the same day, it’s perfect for a quick breakfast or snack.

Three slices of sourdough chocolate zucchini bread laying on a wooden cutting board next to the rest of the loaf.

As I’ve gotten more into sourdough baking, I decided this year to give some of my older recipes a sourdough twist.

First up? My strawberry zucchini bread. I wasn’t in love with the original, so I thought, why not turn it into a chocolate zucchini bread with sourdough discard instead?

And that’s exactly what I did! I used my sourdough discard zucchini bread recipe as a base (which can also be adapted into muffins, by the way), swapped in some cocoa powder for a rich chocolate flavor, and tossed in some chocolate chips for good measure.

It turned out amazing! I had some friends over for dinner, and we enjoyed it for dessert - everyone loved it.

With its rich, chocolatey flavor and moist texture, it’s almost as indulgent as a brownie. Plus, it’s a perfect way to use up sourdough discard and zucchini, especially if your garden is overflowing in the summer.

I’m so excited for you to try this sourdough chocolate zucchini bread recipe, and I hope you love it as much as I do!

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Ingredients & Substitutions

Here are some notes on key ingredients. For a full list of ingredients, check out the recipe card below.

Sourdough Discard- Adds moisture to the chocolate zucchini bread. In this recipe, the tangy flavor of the discard is mostly masked by the chocolate.
Zucchini- Use fresh, finely grated zucchini for the best texture. No need to squeeze out the moisture - it helps keep the bread moist.
Dutch-Processed Cocoa Powder- This type of cocoa is less acidic than natural cocoa, giving the bread a smoother, richer, and more balanced chocolate flavor. If you only have natural cocoa powder, you can use it, but the flavor may be slightly tangier.
Chocolate Chips- Semi-sweet chocolate chips add little bits of creamy chocolate in every bite. Feel free to swap in dark chocolate, milk chocolate, or even white chocolate chips.
All-Purpose Flour- Provides structure to the bread while keeping the crumb soft and tender. You can replace up to ⅓ of the all-purpose flour with whole wheat flour for a heartier loaf.
Brown & Granulated Sugar- A mix of mostly brown sugar for its rich, caramel-like flavor and a bit of granulated sugar for extra sweetness.
Applesauce- Adds moisture to the bread without increasing fat, helping to create a tender texture.
Butter- Adds a rich, buttery flavor. Since butter firms up at room temperature, this quick bread is best served warm for a softer texture. You can substitute with vegetable or canola oil if you prefer.
Kosher Salt- I use Diamond Crystal Kosher Salt (2.8 grams per teaspoon). If using table salt or Morton’s, measure by weight or use half the amount to avoid oversalting.

The ingredients to make sourdough chocolate zucchini bread. Each ingredient is labeled with text. They include cocoa powder, eggs, chocolate chips, butter, zucchini, all-purpose flour, baking powder, baking soda, vanilla, applesauce, brown sugar, granulated sugar, sourdough discard, and salt.

Tips for Success

Choose Dutch-processed cocoa powder. Dutch-processed cocoa powder is less acidic than natural cocoa powder, which gives this sourdough chocolate zucchini bread a more balanced chocolate flavor.
Grate zucchini finely. Finely grate the zucchini using a box grater so it mixes easily into the batter. No need to squeeze out the moisture - it helps keep the bread nice and moist.
Use room temperature ingredients. For a better textured bread, use room temperature eggs, sourdough discard, and applesauce to make the batter.
Don't overmix. Stir the batter just until combined to avoid ending up with a dense loaf.
Cool completely before slicing. Let the bread cool completely before slicing - this helps the crumb set and prevents it from turning mushy.
Serve warm. Quick breads made with butter tend to firm up as they cool since butter solidifies at room temperature. A quick 10–15 seconds in the microwave or a short warm-up in the oven will soften the slices perfectly.

How to Make Sourdough Chocolate Zucchini Bread

Here is how to make chocolate zucchini bread with sourdough discard.

Step 1: Prepare oven and loaf pan. Preheat your oven to 350℉. Grease a 9"x5" loaf pan with butter, oil, or cooking spray, and line it with a strip of parchment paper that hangs over the short edges for easy removal.

Step 2: Mix dry ingredients. In a medium bowl, whisk together the flour, cocoa powder, baking powder, baking soda, and salt. Set aside.

The dry ingredients mixed together in a bowl.

Step 3: Prepare wet ingredients. In a large mixing bowl, whisk the melted butter, brown sugar, and granulated sugar until smooth and slightly lighter in color. Add the eggs, one at a time, whisking well after each addition. Stir in the sourdough discard, applesauce, vanilla extract, and grated zucchini until fully combined.

The wet ingredients mixed together in a bowl.

Step 4: Combine wet and dry ingredients. Gently fold the dry ingredients into the wet mixture until just combined, being careful not to overmix. Fold in the chocolate chips until evenly distributed.

Sourdough chocolate zucchini bread batter in a bowl with a spoon sticking out.

Step 5: Fill loaf pan. Pour the batter into the prepared loaf pan and spread it evenly into all four corners of the pan.

The finished batter spread into a standard loaf pan lined with parchment paper.

Step 6: Bake bread. Bake for 65–75 minutes, or until a skewer inserted into the center of the loaf comes out clean.

Step 7: Cool and serve. Let the bread cool in the pan for 10 minutes, then use the parchment overhang to lift it out and transfer it to a wire rack. Allow it to cool completely before slicing. Serve warm for the best texture.

The baked sourdough chocolate zucchini bread in a parchment-lined loaf pan on a cooling rack.

How to Store

Store completely cooled bread in an airtight container at room temperature for 3-4 days. For the best texture, warm up individual slices in the oven or microwave for 10-15 seconds before serving.

For longer storage, freeze the bread in a freezer-safe container for up to 3 months. Thaw at room temperature and warm before serving.

Slices of sourdough chocolate zucchini bread laying on a piece of wrinkled parchment paper.

A cover of a recipe ebook with the title "Everyday Sourdough: 27 Sweet & Savory Sourdough Discard Recipes." There is an image of sourdough discard cinnamon rolls on the front. At the bottom, it reads "By Ashley Petrie of Everyday Homemade."

Grab a copy today!

Are you tired of watching your sourdough discard go to waste?

It’s time to turn excess discard into something delicious with my new ebook - Everyday Sourdough!

Inside, you’ll find 27 tried-and-true sourdough discard recipes that will transform your leftover starter into mouthwatering creations your family and friends will love.

No more guilt about wasting your discard - with Everyday Sourdough, you have endless options to quickly make something amazing anytime.

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