Sourdough Chocolate Cake with Homemade Chocolate Frosting

Sourdough and chocolate? You bet. If you’ve been baking sourdough bread for a while and are looking to branch out into the dessert world, this Sourdough Chocolate Cake with Homemade Chocolate Frosting is your dream come true. It’s tender, rich, ultra-chocolatey, and unbelievably moist—all thanks to the magic of sourdough starter.

In this post, I’ll walk you through:

• Why sourdough is incredible in cake (and not just bread!)

• The science of chocolate cake made with starter

• Step-by-step photos and baking techniques

• How to make luscious, creamy homemade chocolate frosting

• Variations like sourdough chocolate cupcakes or layer cake

• Storage, make-ahead, and freezing options

• Pinterest SEO keywords and Pin description

• Tips for beginners and expert sourdough bakers alike!

Why Use Sourdough in Chocolate Cake?

Let’s talk about the star ingredient: sourdough starter. You may be used to using it for artisan loaves, discard crackers, or pizza crusts—but trust me, adding it to chocolate cake might just change your baking game forever.

Here’s what sourdough does in a cake:

• Adds moisture and depth: The natural acidity from the starter enhances the flavor of cocoa powder, making the chocolate taste deeper and richer.

• Creates a tender crumb: The long fermentation or just the addition of discard softens the gluten for a melt-in-your-mouth texture.

• Reduces waste: This is a delicious way to use up extra sourdough discard.

Bonus: Nobody will know it’s sourdough. This cake doesn’t taste sour—it tastes like the best chocolate cake you’ve ever had.

Ingredients for the Sourdough Chocolate Cake

For the Cake:

• 1 cup (240g) sourdough starter (active or discard)

• 1 cup (240g) whole milk, room temperature

• 1 ½ cups (180g) all-purpose flour

• 1 ½ cups (300g) granulated sugar

• ¾ cup (64g) unsweetened Hershey's cocoa powder

• 1 tsp baking soda

• ½ tsp salt

• 2 tsp vanilla extract

• ½ cup (120g) vegetable oil (or melted butter)

• 2 large eggs, room temperature

• ½ cup (120g) hot coffee or boiling water (helps bloom the cocoa)

For the Chocolate Frosting:

• ½ cup (1 stick / 113g) unsalted butter, softened

• ½ cup (45g) unsweetened Hershey's cocoa powder

• 2 cups (240g) powdered sugar

• ¼ cup (60ml) whole milk or cream

• 1 tsp vanilla extract

• Pinch of salt

Optional toppings: chocolate shavings, sea salt, sprinkles, or berries.

Equipment You’ll Need

• 2 (8- or 9-inch) round cake pans OR a 9x13 pan

• Stand mixer or electric hand mixer

• Mixing bowls

• Whisk and spatula

• Cooling rack

• Offset spatula (for frosting)

Step-by-Step: How to Make the Best Sourdough Chocolate Cake

Step 1: Mix the Sourdough Batter Base

In a large bowl, combine:

• 1 cup sourdough starter

• 1 cup milk

• 1 ½ cups flour

Stir until fully incorporated. Cover the bowl and let it rest at room temperature for 2 to 4 hours. This rest hydrates the flour and allows some fermentation to begin, which results in better flavor and texture.

Tip: This step is optional, but highly recommended if you have the time. If not, you can move forward right after mixing.

Step 2: Preheat and Prep

Preheat oven to 350°F (175°C).

Grease and line your pans with parchment paper to prevent sticking. For round cakes, trace the bottom and cut out perfect parchment circles.

Step 3: Mix the Cake Batter

In a separate large bowl, whisk together:

• 1 ½ cups sugar

• ¾ cup Hershey's cocoa powder

• 1 tsp baking soda

• ½ tsp salt

Add to that:

• 2 large eggs

• 2 tsp vanilla

• ½ cup oil

• ½ cup hot coffee or water

Mix until fully combined.

Now add the sourdough mixture from Step 1 into the chocolate batter. Stir until no lumps remain. You should have a thick, smooth, rich batter.

Step 4: Bake the Cake

Divide the batter evenly between your prepared pans.

Bake for:

• 30–35 minutes for round pans

• 35–40 minutes for a 9x13 pan

Test doneness with a toothpick—it should come out with a few moist crumbs.

Cool in the pans for 10 minutes, then transfer to wire racks to cool completely.

How to Make Homemade Chocolate Frosting

While the cake cools, make the frosting.

Step 1: Cream Butter and Cocoa

In a bowl, beat:

• ½ cup butter

• ½ cup Hershey's cocoa powder

Beat until smooth and fluffy.

Step 2: Add Powdered Sugar and Milk

Slowly beat in:

• 2 cups powdered sugar

• ¼ cup milk

• 1 tsp vanilla

• Pinch of salt

Beat for 3–4 minutes until light, fluffy, and glossy.

If it’s too thick, add 1 tbsp more milk at a time. If too thin, add more powdered sugar.

Step 3: Frost the Cake

Once the cake is completely cool, spread the frosting generously between layers and over the top and sides. An offset spatula helps smooth things out beautifully.

Top with shaved chocolate, flaky sea salt, or berries for a stunning finish.

Customizations and Variations

Make it a Layer Cake: Split into 3 layers and add ganache between each for an ultra-decadent dessert.

Sourdough Chocolate Cupcakes: Bake in a lined muffin tin for 18–20 minutes.

Add Mix-Ins: Stir in chocolate chips, chopped walnuts, or espresso powder for a deeper flavor.

Use Different Frosting: Cream cheese, mocha buttercream, peanut butter frosting, or even a whipped ganache all work beautifully.

How to Make This Cake Ahead

• Bake and freeze the layers: Wrap cooled layers tightly in plastic wrap and freeze for up to 2 months.

• Make frosting ahead: Store in an airtight container in the fridge for up to 1 week. Bring to room temp and re-whip before using.

• Fully assembled cake: Can be kept at room temp for 1 day or in the fridge up to 4 days.

Storage Tips

• Room Temp: Store in a cake dome or airtight container for up to 3 days.

• Fridge: Store for up to 5–7 days. Bring to room temp before serving for best texture.

• Freezer: Freeze slices wrapped individually in plastic wrap and foil for up to 3 months.

Expert Tips for Perfect Cake Every Time

• Don’t skip the coffee or hot water. It deepens the chocolate flavor and activates the cocoa powder.

• Use room temperature ingredients so the batter emulsifies properly.

• Cool completely before frosting—otherwise, your frosting will melt right off.

• Use Dutch-processed cocoa for the richest, darkest flavor.

• Measure ingredients by weight for accuracy.

FAQs About Sourdough Chocolate Cake

Can I use discard instead of active starter?
Yes! Discard works well in this recipe since the rise comes from baking soda, not fermentation.

Will it taste sour?
Nope! The chocolate and sugar balance out the tang of the starter.

Can I make this gluten-free?
You can try using a 1:1 gluten-free flour blend, though texture may vary.

What’s the best cocoa powder?
Dutch-processed cocoa gives the richest flavor, but any unsweetened cocoa will work.

Reader Reviews

⭐⭐⭐⭐⭐ “This was the best chocolate cake I’ve ever made—and I’ve made a lot! The sourdough made it so moist and flavorful. Huge hit with my family.” – Jessica

⭐⭐⭐⭐⭐ “I used my discard and it came out perfectly! Made it into cupcakes for a birthday party and they disappeared in minutes.” – Sam

⭐⭐⭐⭐⭐ “I’ve tried a few sourdough chocolate cakes and this one is hands-down the winner. The homemade frosting is incredible too.” – Lena

Final Thoughts

Sourdough chocolate cake is the kind of recipe that makes you fall in love with your starter all over again. It's indulgent, beautiful, and so easy to make for any celebration or craving. Whether you’re new to sourdough or a seasoned baker, this cake will wow your taste buds and become a new go-to in your baking repertoire.

If you loved this recipe, don’t forget to Pin it, share it with your baking friends, and let me know in the comments how it turned out. And if you want more sourdough dessert recipes, check out my sourdough brownies, discard cupcakes, and cinnamon sugar loaf!