Sponge Cake Sourdough Brownies

Name: Sponge Cake Sourdough Brownies
Prep time: 30 min
Cook time: 25 min
Total time: 55 min
Yield: 12 brownies
Ingredients: 1 cup unsalted butter; 2 cups granulated sugar; 4 large eggs; 1 cup unsweetened cocoa powder; 1 cup all-purpose flour; 1 teaspoon baking powder; 1/2 teaspoon salt; 1 cup sourdough starter; 4 large eggs; 1 cup granulated sugar; 1 cup all-purpose flour; 1/2 cup milk; 1/4 cup vegetable oil; 1 teaspoon vanilla extract; 1 teaspoon baking powder; 1/2 teaspoon salt

Highlighted under: Dessert Recipe Collection

I absolutely adore baking these Sponge Cake Sourdough Brownies for gatherings and special occasions. The unique combination of sponge cake and brownie gives them a light yet indulgent texture that everyone loves. With the tangy hint of sourdough, these brownies elevate a classic dessert into something truly unforgettable. It's fulfilling to watch friends relish every bite while I share the story of my baking journey with sourdough. I believe that the best recipes are those that bring people together, and these brownies do just that.

Created by

Emma Johnson

Last updated on 2026-01-27T12:53:27.937Z

Baking Sponge Cake Sourdough Brownies has become my secret weapon when I want to impress guests. I experimented with combining my favorite sourdough starter into a rich brownie base and found that it adds a depth of flavor making the brownies less sweet, yet satisfying. The sponge cake layer creates a delightful contrast in texture, making each bite truly special.

Through trial and error, I discovered that allowing the sourdough to rest in the batter creates a harmonious blend of flavors. Learning how to balance the ingredients was key—if you let the brownies cool completely, you'll achieve that perfect, fudgy center. It's a sensation that will have everyone asking for seconds!

Why You'll Love These Brownies
Unique combination of light sponge and rich brownie textures
Sour tang from the sourdough adds a sophisticated flavor
Perfect treat for any occasion that will impress your guests

Understanding the Texture

The unique structure of these Sponge Cake Sourdough Brownies comes from the interplay between the brownie and sponge cake layers. The brownies provide a dense, fudgy base, while the sponge layer on top introduces a light, airy texture. This contrast is essential; when the brownie layer is baked correctly, you should see the edges pulling away slightly from the pan and the top layer should be golden and slightly springy to the touch.

To achieve the best texture in your brownies, ensure that the butter is melted but not too hot when mixing with the sugar. If the butter is too hot, it can cook the eggs, creating an undesirable consistency. A visual cue to look for is a glossy and thick brownie batter before you add the sourdough starter, which gives the brownies their unique flavor.

Ingredient Insights

The use of sourdough starter is what truly elevates these brownies from ordinary to extraordinary. It adds not only a subtle tang that balances the sweetness but also enhances moisture, making the brownies stay fresh longer. If you're out of sourdough starter, you can substitute it with an equal amount of buttermilk or yogurt, adjusting the dry ingredients slightly to maintain the right consistency.

Eggs are crucial in both layers; they provide structure and help in leavening the sponge cake. Always use large eggs, as size can affect the batter's hydration. If you're looking for a lighter option, you can replace two of the large eggs in the sponge layer with egg whites, which will make it fluffier without compromising flavor.

Ingredients

Gather these amazing ingredients to make your Sponge Cake Sourdough Brownies:

Brownie Layer

1 cup unsalted butter
2 cups granulated sugar
4 large eggs
1 cup unsweetened cocoa powder
1 cup all-purpose flour
1 teaspoon baking powder
1/2 teaspoon salt
1 cup sourdough starter

Sponge Cake Layer

4 large eggs
1 cup granulated sugar
1 cup all-purpose flour
1/2 cup milk
1/4 cup vegetable oil
1 teaspoon vanilla extract
1 teaspoon baking powder
1/2 teaspoon salt

Make sure to have all these ingredients ready before you start baking!

Instructions

Follow these precise steps to create your delicious brownies:

Prepare the Brownie Batter

Preheat your oven to 350°F (175°C). In a large mixing bowl, melt the butter and stir in the sugar until well combined. Beat in the eggs one at a time, then mix in the cocoa powder, flour, baking powder, and salt. Finally, fold in the sourdough starter until the brownie batter is smooth and well mixed.

Make the Sponge Cake Batter

In another bowl, beat the eggs and sugar until pale and fluffy. Gradually mix in the flour, then add the milk, oil, vanilla, baking powder, and salt. Whisk until the mixture is smooth and bubbly.

Layer and Bake

Grease a baking pan and pour the brownie batter into the bottom. Gently spoon the sponge cake batter over the brownie layer—do not mix. Bake for about 25 minutes, or until a toothpick inserted into the sponge layer comes out clean.

Cool and Serve

Allow the brownies to cool completely in the pan before slicing. This helps set the layers and makes for neater pieces. Enjoy these brownies as they are, or dust them with powdered sugar for a fancy touch!

Enjoy making these delightful brownies!

Pro Tips

For an extra burst of flavor, consider adding chocolate chips to the brownie layer or a hint of orange zest to the sponge. Always let your brownies cool completely to ensure a fudgy texture.

Storage and Make-Ahead Tips

These brownies can be made ahead of time and stored for up to a week in an airtight container at room temperature. To ensure they remain moist, consider placing a piece of bread inside the container. If you need to keep them for longer, they freeze beautifully. Just wrap them in plastic wrap and then foil, storing them in the freezer for up to three months. Thaw at room temperature before serving for best results.

If you plan to serve these at a later date, consider adding the powdered sugar dusting right before serving. This keeps the visual presentation fresh and the texture of the sugar intact, providing that delightful contrast against the moist brownies.

Serving Suggestions

These Sponge Cake Sourdough Brownies are versatile when it comes to serving options. You might enjoy them plain, but consider pairing them with a dollop of whipped cream or a scoop of vanilla ice cream. The creamy textures complement the tangy sweetness beautifully. Adding fresh berries on top can also enhance the visual appeal and provide a refreshing contrast to the rich flavors.

For a gourmet twist, serve the brownies with a drizzle of chocolate ganache or a homemade caramel sauce. This not only adds a luxurious texture but also heightens the chocolate experience. Additionally, experiment with serving them warm; gently reheating in the microwave for 10-15 seconds can bring out the fudgy center, creating a delightful melting experience.

Questions About Recipes

→ Can I use a different type of flour?

Yes, you can substitute all-purpose flour with gluten-free flour, but keep in mind the texture may vary.

→ How should I store the brownies?

Store them in an airtight container at room temperature for up to 4 days, or refrigerate for a week.

→ Can I freeze these brownies?

Absolutely! Wrap them tightly and freeze for up to 3 months. Thaw at room temperature before serving.

→ What can I do if my sourdough starter is too thick?

You can add a little water to thin it out, but make sure not to compromise the texture of your brownie mix.