Name: Chocolate Sourdough Cake (Triple Chocolate Matilda Cake)
Prep time: 10 min
Cook time: 30 min
Total time: 160 min
Ingredients: 3 cups all-purpose flour; 1/2 cup Dutch-processed cocoa powder (unsweetened cocoa powder works too); 1 tablespoon baking soda; 1/2 teaspoon salt; 1 cup melted butter; 2 1/2 cups granulated sugar; 4 large eggs; 2 teaspoon vanilla extract; 1 cup sour cream (room temperature); 1 cup sourdough discard (room temperature); 1 cup coffee (warm, but not boiling); 1/2 cup semi-sweet chocolate chips; 1/4 cup heavy cream; 1 cup salted butter (2 sticks, room temperature); 8 ounces cream cheese (full fat, room temperature); 1/2 cup sour cream (room temperature); 2 teaspoons vanilla extract; 4 cups powdered sugar (sifted); chocolate ganache (recipe above)

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This sourdough discard chocolate cake is reminiscent of the classic Matilda cake that Bruce Bogtrotter ate in the movie! It’s a moist three layer triple chocolate cake that includes frosting with a two-ingredient chocolate ganache mixed into the chocolate cream cheese frosting.

A closeup picture of a slice of sourdough chocolate cake.

When I say this is my favorite flavored cake, I mean it! I am a HUGE chocolate fan, so this triple chocolate cake with three layers is moist, decadent, and topped with the creamiest chocolate fudge frosting.

It makes a fantastic birthday cake and uses sourdough discard (active starter works too!). If you’re looking to wow guests and use up that extra sourdough discard, this recipe is the one to make!

This chocolate sourdough discard cake is a variation of my delicious and super popular sourdough chocolate cupcakes!

Looking for more sourdough baked goodness? Check these recipes out:

A closeup of the inside of the triple chocolate sourdough cake with chocolate fudge frosting. It sits on a cake stand with parchment paper on it.

Ingredients

granulated sugar
melted butter – I always use salted butter. If you only have unsalted butter, you can use that. Add an extra 1/4 teaspoon of salt to the recipe.
eggs – Take the eggs out of the fridge an hour before you plan to bake the cake. Room temperature eggs make fluffy, moist cakes!
all-purpose flour
sourdough discard – active starter or inactive discard works here.
vanilla extract
sour cream – use room temperature sour cream. Alternatively, you can use room temperature full fat Greek yogurt.
coffee – brewed coffee is best for this chocolate cake. It can be warm, but not boiling. Alternatively, you can use warm water–it just won’t provide as deep of a flavor.
Dutch-processed cocoa powder – I prefer Dutch-processed cocoa powder for a darker color and smoother taste, but if you only have cocoa powder, that works too!
salt
baking soda

The ingredients needed for the chocolate cream cheese frosting: Dutch-processed cocoa powder, salted butter, vanilla extract, sour cream, powdered sugar, heavy cream, semi-sweet chocolate chips.

salted butter – I always use salted butter. If you have unsalted butter only, add an extra 1/4 teaspoon of salt.
sour cream – room temperature sour cream is necessary for a smooth texture.
cream cheese again, room temperature cream cheese is needed so you don’t get lumps. I use full-fat block-style cream cheese.
vanilla extract
powdered sugar – sift the powdered sugar beforehand to avoid clumps of sugar in your frosting.
salt
semi-sweet chocolate chips and heavy cream – I use these two ingredients to make a simple chocolate ganache that I fold into the frosting. This step is optional, but adds even more chocolatey goodness to this cake! You can use semi-sweet chocolate chips or dark chocolate chips.

Step-By-Step Instructions

A glass mixing bowl of the dry ingredients for the sourdough chocolate cake.

Preheat your oven to 350°F. Grease three 9-inch round cake pans and line the bottoms with parchment paper for easy release. Set the pans aside while you prepare the batter.

In a large bowl, sift together the flour, cocoa powder, baking soda, and salt. Set aside.

A glass mixing bowl of the melted butter, sugar, eggs, and vanilla.

In another large bowl, whisk together the melted butter and sugar until well combined. Add the eggs one at a time, whisking well after each addition, then stir in the vanilla extract.

A glass mixing bowl with all the wet ingredients needed for the cake mixed together.

Next, fold in the sour cream and sourdough discard until everything is fully incorporated.

A glass mixing bowl with all the cake batter in it. A rubber spatula sits in the bowl.

Gradually add the dry ingredients to the wet mixture, mixing just until combined. Then pour in the warm coffee and gently stir until the batter is smooth. It will loosen up and become silky — exactly what you want for a rich, moist cake.

Three round cake pans filled with cake batter.

Divide the batter evenly between the three prepared pans. Bake for about 30 minutes, or until a toothpick inserted into the center comes out clean.

Three round cakes cooling on three wire racks.

Let the cakes cool in the pans for about 10 minutes before turning them out onto a wire rack to cool completely.

Chocolate ganache in a mixing bowl with a whisk in the bowl.

While the cakes cool, make the chocolate ganache. Fill a small saucepan with a few inches of water and bring it to a gentle simmer.

Place the chocolate chips and heavy cream in a heatproof glass bowl, then set the bowl over the saucepan, making sure the bottom of the bowl doesn’t touch the water.

Stir the mixture gently until the chocolate is fully melted and the ganache is smooth and glossy. Remove from the heat and let it cool slightly before using.

The chocolate fudge cream cheese frosting mixed together in a glass mixing bowl.

To make the frosting, beat the room-temperature butter and cream cheese together in a large bowl until creamy and smooth. Mix in the sour cream and vanilla extract, then gradually add the sifted powdered sugar.

Once the frosting is fluffy, pour in the cooled chocolate ganache and continue beating until the frosting is rich, silky, and fully combined. If needed, chill the frosting briefly to firm it up before decorating.

Once the cakes are completely cooled, place one layer on a serving plate and spread a generous amount of frosting over the top.

Add the second layer, frost, then add the third. Cover the top and sides of the cake with the remaining frosting, smoothing it out as you go.

A sourdough chocolate triple layered cake sits on a wooden cake stand. Two slices are cut out of it. Those slices of cake sit on two separate plates.

Equipment Needed to Bake This Chocolate Sourdough Cake

three round 9-inch cake pans
two mixing bowls
stand mixer or electric mixer
whisk
cake strips (optional, but helps to bake even-topped cakes)

Top Tips for Making This the BEST Cake!

Don’t overmix the batter.
Once you add the dry ingredients and coffee, mix just until everything is combined. Overmixing can create a dense or dry cake instead of a tender, moist crumb.

Use room temperature ingredients.
Make sure the sour cream, sourdough discard, eggs, and butter are at room temperature before you start. This helps them blend more smoothly into the batter, creating an even texture and locking in moisture.

Check for doneness early.
Start checking the cakes a few minutes before the timer goes off. Overbaking even by a few minutes can dry out chocolate cake. The cake is done when a toothpick comes out with a few moist crumbs, not completely clean.

The kitchen scale is your friend. If you’re looking for even cake layers, use a kitchen scale to measure out the batter in each pan before you bake them.