Sourdough chocolate cake

This soft and fluffy chocolate cake is made from discarded sourdough starter. It’s slightly tangy and slathered in a divine layer of chocolate buttercream!

sourdough chocolate cake

YOU GUYS. I did it! I conquered a baking fear – I baked with sourdough starter! You see, I’ve read about sourdough and have always been intrigued. But honestly, it scared the heck outta me. This little blob of flour and water needed to be fed twice a day to stay alive? Sounds like a child if you ask me.

However, a coworker of mine convinced me to try it. She even met me in town to gift me part of her sourdough starter. She talked me through the process and told me about all these wonderful recipes to make with the discarded starter. Of course, I was still skeptical and scared, but I persisted.

sourdough chocolate cake

The first project I tackled (notice that I said THE FIRST… heh heh) was this sourdough chocolate cake. My coworker told me that it was an awesome recipe, and I didn’t even need to feed the starter to bake this. OK then – sold.

I attempted to feed my starter a little bit and made sure I had enough to bake the cake. And you know what? It was pretty easy! My cake poofed up in the oven and stayed puffy after cooling (yay, yeast!). I cut the cake level and ate the scraps as my reward. Then I frosted it with some chocolate buttercream, and Addie threw on some rainbow sprinkles.

sourdough chocolate cake

I’m so proud of myself for baking something with sourdough starter! Now, can I keep up with the feedings and keeping this thing alive? I don’t know, but I guess we’ll find out.

Husband’s rating: 4 out of 5
Addie’s rating: 4 out of
My rating: 4 out of 5

sourdough chocolate cake
Print Recipe
5 from 1 vote

Sourdough chocolate cake

Don't throw away your sourdough discard! Make this SCRUMPTIOUS chocolate cake with it instead! Frosting totally not optional, of course.
Prep Time15 minutes
Cook Time40 minutes
Resting time3 hours
Total Time3 hours 55 minutes
Course: Dessert
Cuisine: American
Keyword: Cake
Servings: 24
Author: Eva Bakes



  • 1 cup (227 grams) sourdough starter ripe (fed) or discard
  • 1 cup (227 grams) milk whole milk or 2% preferred; can substitute with evaporated milk
  • 2 cups (214 grams) all-purpose flour
  • 1 and ½ cups (298 grams) granulated sugar
  • 1 cup (198 grams) vegetable oil
  • 2 teaspoons vanilla extract
  • 1 teaspoon salt
  • 1 and ½ teaspoons baking soda
  • ¾ cup (64 grams) unsweetened cocoa powder NOT dutch process
  • 1 teaspoon instant espresso powder optional
  • 2 large eggs

Frosting (this is enough for a half batch of cake - double it if baking the entire 9"x13" cake recipe)

  • ½ stick (4 Tablespoons) unsalted butter room temperature
  • ½ cup unsweetened cocoa powder
  • 2 cups powdered sugar
  • 2-3 teaspoons milk of choice
  • 1 teaspoon vanilla
  • pinch salt


Make the cake

  • In a large bowl, mix together the sourdough starter/discard, milk and flour. Cover and allow to rest in a warm spot for 2-3 hours. The dough might get bubbly or expand.
  • Once 2-3 hours has passed, preheat your oven to 350°F. Generously grease or line a 9"x13" pan and set aside.
  • In the bowl of a stand mixer fitted with the paddle attachment, whisk together the sugar, oil, vanilla, salt, baking soda, cocoa powder and espresso powder on medium-low speed until combined. The mixture will appear grainy. Add the eggs, one at a time until each is fully incorporated.
  • Add the sourdough mixture and beat on low speed. Be patient - it may start off as a mess, but the dough will slowly come together after a few minutes.
  • Transfer the batter to your prepared pan and smooth the top. Bake in your preheated oven for 30-40 minutes or until a toothpick inserted in the center comes out clean.
  • Remove the pan from the oven and allow to cool completely.

Make the frosting

  • In the bowl of a clean stand mixer fitted with the paddle attachment, beat the butter with the cocoa powder on medium speed until fluffy, about 2-3 minutes.
  • Add the powdered sugar, a little bit at a time. Add the milk, vanilla and salt. If your frosting is too thin for your liking, add more powdered sugar. If it's too thick, add a splash of milk.
  • Once the cake has cooled completely, frost, slice, and serve.


Note: I halved this recipe and baked it in a 8"x8" square baking pan and got 16 slices of cake.
Source: King Arthur Flour


  1. Carolyn
    December 8, 2020 / 11:35 am

    5 stars
    Yummy cake. Turned out beautifully (halved the recipe, baked 8×8); it’s a perfect not-too-sweet snack cake. We didn’t frost it. Everyone had seconds, including a curmudgeonly 93 year old. The fact that is also uses up our ever-growing discard is a plus.

    • evabakes
      December 8, 2020 / 12:51 pm

      Hooray! I’m so glad that the cake turned out and that everyone had seconds! I usually pan-fry up my sourdough discard – I sprinkle on some diced scallions and a pinch of salt. They are delicious little pancakes!

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