Sourdough Discard Chocolate Cake
This sourdough discard chocolate cake is rich, moist, and full of deep chocolate flavor. The discard adds a subtle tang that balances the sweetness, and the easy chocolate buttercream frosting makes it perfect for birthdays, potlucks, or anytime you're craving a classic chocolate cake.
Servings: 18 servings
Ingredients
- 1 cup unsweetened cocoa powder 84 grams
- ¾ cup hot coffee or very hot water 170 grams
- 1¾ cups granulated sugar 350 grams
- ¾ cup vegetable oil 160 grams
- 2 large eggs
- ¾ cup sourdough discard 170 grams
- ½ cup milk 113 grams
- 2 tsp vanilla extract
- 1¼ cups all-purpose flour 150 grams
- 1½ tsp baking powder
- 1½ tsp baking soda
- 1¼ tsp salt
Chocolate Buttercream Frosting
- 1 cup unsalted butter room temp, 226 grams
- ¾ cup unsweetened cocoa powder 63 grams
- 3½ cups powdered sugar sifted; 420 grams
- ¼ cup milk plus more as needed
- 2 teaspoons vanilla extract
- ¼ teaspoon salt
Instructions
- Preheat the oven to 350°F. Line the bottom of a 13x9-inch cake pan with parchment paper. Grease and flour the sides of the pan (no need to line the sides with parchment).
- In a large mixing bowl, whisk together the hot coffee and cocoa powder until smooth. Let it sit for 2–3 minutes to bloom the cocoa. Stir in the sugar and oil until well combined.
- Whisk in the eggs, followed by the sourdough discard, milk, and vanilla extract. Mix until smooth.
- Sift the flour, baking powder, baking soda, and salt over the wet ingredients. Stir until just combined, making sure to scrape the bottom and sides of the bowl. The batter will be thin.
- Pour the batter into the prepared pan and bake for 33–38 minutes, or until a toothpick inserted in the center comes out clean.
- Let the cake cool in the pan for 5–10 minutes. Run a knife around the edges to loosen, then either leave it in the pan for serving or invert it onto a wire rack to cool completely before transferring to a serving platter.
Make the Frosting
- Beat the butter in a large bowl until pale and fluffy, 2–3 minutes.
- Add cocoa powder and mix until smooth.
- Gradually mix in the powdered sugar, starting on low and increasing speed as it incorporates.
- Add the milk, vanilla, and salt. Beat until smooth and fluffy, about 2–3 minutes.
- Adjust consistency: add more milk 1 teaspoon at a time if it’s too thick, or more powdered sugar if it’s too soft.
Frost the Cake:
- Once the cake is completely cool, spoon the frosting onto the center and spread it evenly over the top. If the cake is still in the pan, you can skip the sides. If it’s been inverted onto a platter, feel free to frost the sides as well.
Notes
Sourdough Discard: Use unfed discard that’s relatively fresh (ideally within a week old). Discard that’s been sitting too long tends to have a higher acid content, which can affect the flavor and texture of the cake. You don’t need an active or bubbly starter here, but skip anything that smells overly sharp or has separated into layers.
Coffee Substitute: If you don’t want to use coffee, very hot water works just fine.
Batter Consistency: The batter will be thin, don’t worry, that’s exactly how it should be. It bakes up moist and tender.
Frosting: Make sure the cake is fully cooled before frosting, or the buttercream will melt.
Storage: Store frosted cake covered at room temperature for up to 2 days, or refrigerate for longer storage. Bring to room temp before serving for best texture.
Freezing: The cake freezes well. Wrap tightly and freeze for up to 2 months. Thaw in the fridge overnight, then bring to room temp before serving.
Nutrition
Serving: 1 serving | Calories: 412kcal | Carbohydrates: 57g | Protein: 4g | Fat: 21g | Saturated Fat: 9g | Polyunsaturated Fat: 6g | Monounsaturated Fat: 5g | Trans Fat: 0.5g | Cholesterol: 47mg | Sodium: 303mg | Potassium: 169mg | Fiber: 3g | Sugar: 43g | Vitamin A: 358IU | Calcium: 51mg | Iron: 2mg
