Overnight Sourdough Chocolate Cake
This chocolate sourdough cake is soft and tender with deep chocolate flavour, filled and topped with creamy chocolate frosting. It is the perfect way to use your sourdough discard starter and makes the best chocolate cake. I like to make the batter the day before and ferment it in the fridge overnight, though you can bake it all in one day too.
About this recipe
This sourdough discard chocolate cake is a rich chocolate layer cake and makes a wonderful birthday cake or cake for any occasion.
The great thing about sourdough discard recipes is that you can save up all the starter discard in a jar in the fridge and use it when you want. Other sourdough starter discard recipes include puff pastry and overnight sourdough pancakes. This sourdough cake recipe doesn’t rely on the yeast in the starter the way that sourdough bread does. It uses the acid produced by the Lactobacillus bacteria in the starter. This starter hasn’t been fed in a while or passed its peak and is now very acidic. That’s not good for sourdough bread, but it’s great for this sourdough chocolate cake (or red velvet cake!)
Don’t have a starter yet? Learn to make your own starter with this sourdough starter recipe.
Ingredients
The actual amounts of the ingredients for this tender chocolate cake recipe are written in the recipe card at the bottom of this post. Here is a rundown of what you need.
- Sugar – There’s a mixture of granulated and brown sugar for sweetness and moisture.
- Large eggs – Eggs act as a binding agent, providing structure and stability. They also add moisture and fat.
- Vanilla paste or good-quality vanilla extract – Vanilla adds depth of flavor, enhancing the chocolate.
- Discard sourdough starter – The sourdough discard contributes a unique, slightly tangy flavor, balancing the sweetness of the cake. The acid in the starter creates a tender cake.
- Vegetable oil. Oil creates a really moist cake. You could use light olive oil, liquid coconut oil, or neutral-tasting vegetable oil.
- Salt – Enhances all the flavors.
- All-purpose flour – The base of the cake.
- Whole milk – Loosens the batter.
- Cocoa powder. This can be natural cocoa powder or Dutch-processed cocoa powder. I prefer the taste of natural cocoa powder though.
- Baking powder and baking soda – The leavening agents in the cake.
- Hot coffee. I use instant espresso powder dissolved in boiling water. If you’re not a fan of coffee, don’t worry, you won’t taste it. The coffee helps to strengthen the chocolate flavor. If you want to leave it out, it can be substituted for hot water.
Fermented chocolate cake
I like to make the batter the night before and leave it to ferment in the fridge overnight. This helps break down the starches in the flour and helps with digestion. I have done a side-by-side test of baking the batter all in day one versus an overnight ferment and found no real difference in the height of the cakes when baked or the flavour, so it’s an optional step.
Method
- Whisk together the flour, cocoa, salt, baking powder, and baking soda and set it aside.
- In a separate bowl, whisk together the sourdough starter, eggs, vanilla, oil, milk, and sugars.
- Pour the wet ingredients into the flour mixture and fold gently for a minute before pouring over the hot coffee.
- Cover the bowl tightly and ferment overnight, or go right to baking.
- Divide the batter evenly over two 8-inch cake pans and bake.
- Mix the frosting by beating butter until creamy, then powdered sugar, cocoa powder, milk, vanilla, and salt til creamy.
- Spread 1/3 of the buttercream on one cake round so it reaches the edges. Add the second cake round on top. Spread with the remaining buttercream.
FAQs about sourdough chocolate cake
Variations
- Sourdough chocolate orange cake: Add the zest of an orange into the batter, and replace half of the milk with fresh orange juice.
- Chocolate raspberry cake: On the first layer of cake, spread out some of the frosting, then pipe a wide ring of frosting around the edge. Spoon in a layer of raspberry compote. Add the second layer of cake, and continue frosting with chocolate buttercream.
- Sourdough mint chocolate cake: Add 1/4 teaspoon peppermint extract to your cake batter and 1 teaspoon peppermint extract to the chocolate buttercream frosting.
Related recipes
Keen to make some other delicious recipes? Try this sourdough red velvet cake or other sourdough recipes that are not bread, like sourdough croissants or homemade sourdough waffles.
Sourdough Chocolate Cake
Ingredients
Cake batter
- 220 g all-purpose flour
- 70 g cocoa powder unsweetened. I prefer natural cocoa powder
- 3/4 tsp salt
- 1 tsp baking powder
- 1 tsp baking soda
- 2 large eggs
- 1 tsp vanilla extract
- 180 g vegetable oil
- 100 g sourdough discard starter
- 130 g granulated sugar
- 130 g soft brown sugar
- 240 g milk
- 120 g coffee hot and strong
Chocolate Buttercream
- 226 g butter softened to room temperature
- 300-375 g powdered sugar
- 30 g cocoa powder
- 1/2 teaspoon vanilla paste
- 2-3 Tbsp milk or cream at room temperature
- 1/4 tsp salt
Instructions
- Mix the flour, cocoa powder, salt, baking powder, and baking soda in a large bowl. Set it aside.
- Whisk together the sourdough starter, eggs, vanilla, oil, milk, and sugars in a separate bowl.
- Pour the wet mixture into the flour mixture and fold gently for a minute before pouring over the hot coffee.
- Mix briskly together but don't over-mix.
- Fermenting overnight (optional) – Cover the bowl tightly and refrigerate for up to 12 hours.
- Heat the oven to 180°C (350°F). Grease and line two 8-inch round cake pans.
- Pour into the prepared cake pans and bake for 25-30 minutes until a skewer inserted into the cakes comes out clean.
Chocolate Buttercream
- In a stand mixer bowl fitted with a paddle attachment, beat the room-temperature butter until light and creamy.
- Add the powdered sugar, cocoa powder, milk, vanilla, and salt to the butter.
- Whisk on low speed to incorporate them, scraping the sides of the bowl as needed. Once incorporated, switch to medium-high speed and beat the mixture for another 1-2 minutes until it's light and fluffy.
- Spread 1/3 of the buttercream on one cake round so it reaches the edges. Add the second cake round on top. Spread with the remaining buttercream.
Hi, thanks for this (and your other recipes). Just wondering whether you use Dutch process cocoa or the non-Dutch kind for this recipe? I believe Dutch process is neutral pH whereas the other kind is acidic, so choice may affect rising. But perhaps it doesn’t matter that much since acidity is taken care of by the starter and cream of tartar in baking powder (and acidity of starter varies a bit anyway. Thanks!
Heya Mike, I’ve used both natural and Dutch processed cocoa in this cake and haven’t seen a noticeable difference 🙂
I just pulled them (used two) out of the fridge and turned the oven on. I can’t wait to see the results, oh my!
Thanks for posting! I am always looking for new ways to use my sourdough starter. Made this yesterday – my recommendation is to split between two 8 or 9 inch pans. I used one 9 inch pan and the center took much longer to bake than the edges, making the outer part of the cake a bit dry and chewy while the center was lovely and moist. I look forward to making this again!
The picture shows two layers but the directions indicate one nine-inch round or two seven-inch pans. A boxed cake mix usually makes 12 servings but requires two eight-inch pans.
There are no instructions for assembly.
In the nutritional listing a serving size is 1 gram???
Please clarify.
Hey, there are instructions on icing the cake in the actual post. If using one cake tin it can be sliced in half to make two layers. You can also use 2×8 inch pans if you like.
The nutrition info is for one 1/12 cake slice, not including the icing. It’s using a calculator that for some reason says 1 gram and I’m unsure how to change that! so i had already added information about the serving size in the notes under the recipe. 🙂 Thanks
EDIT to above comment:
I have been baking nearly 60 years (also taught cake decorating and confectionery arts for many years) and my older daughter’s first birthday was celebrated with a chocolate sourdough cake – she’s turning 50 this year! In all those years, you can only imagine how many recipes I have tried, and I must, quite truthfully, say I never found a better chocolate cake recipe than this one! Sourdough or otherwise.
As one other reviewer mentioned, I used two 8″ round pans and that was perfect for the amount of batter. The cake kept very well at room temperature for a week. I did use a different recipe for the icing, though. All in all, this cake deserves at least 8 stars out of 5 in my opinion. 😉
Can i use butter or coconut oil instead of vegetable oil? If so what would be the measurements? Thank you!
Slightly warmed coconut oil so it’s liquid works, the same amount 🙂
If I do the long ferment in the fridge, should I wait to add the baking powder and soda until I bake it? And, can this ferment on the counter instead of the fridge if my house is cold?
You might get a higher rise if you wait to add them in but I’ve usually ferment once it’s already in there and still get a good rise :). You can ferment it on the bench instead
If I cannot have coffee what would be a good substitute?
Hey Katie you can just use boiled water 🙂
i made this it was sooooooooooo good!
Yay that’s great to hear Olivia!
I would love to try this but I don’t have discard sourdough. What happens if you use regular sourdough starter?
Hey Ginny, the more acidic the starter the better the rise in this cake, so you can just leave your starter to rise and deflate before using it 🙂
This is officially the best chocolate cake I have ever made! I have been looking all over for the perfect chocolate cake and my sister has been making sourdough in lockdown so we have been trying many discard recipes. It was so moist and had a perfect rich flavour. I made a chocolate whipped cream which I put inside the cake and all of my family adored it. I will be checking out more of your recipes for sure!
That’s the best feedback, thank you! 😀
Super delicious. It’s just my boyfriend and I, so I cut the recipe in half. The cake isn’t overly sweet which I liked. Didn’t use the frosting or anything but I’m sure it adds a wonderful sweetness.
So glad you enjoyed the recipe Hannah! 🙂