A decadent chocolate cake with sourdough starter. Filled with creamy chocolate buttercream and topped with a rich chocolate ganache.
The great thing about a recipe like this that uses sourdough discard starter is that you can simply save up all the starter discard in a jar in the fridge and use it when you want.
That’s where this decadent sourdough chocolate cake comes in.
This recipe doesn’t rely on the yeast in the starter the way that sourdough breads do. It needs the acid that’s produced by the Lactobacillus bacteria in the starter.
This is the starter that hasn’t been fed in a while, or it has passed its peak and has become runny or split. This means the yeast in the starter has run out of food and the starter is now very acidic. That’s not good for sourdough bread, but it’s great for this sourdough chocolate cake.
The cake is made up by first mixing the dry ingredients: flour, cocoa powder, salt, a little baking powder and baking soda.
Then in a separate bowl, the wet ingredients and sugars are mixed together: eggs, vanilla extract, oil, sourdough starter, brown sugar, white sugar and milk.
Half a cup of hot coffee is added to the cake batter at the end. Not a fan of coffee? Don’t worry, you won’t taste it! It just strengthens the chocolate flavour in the cake.
Why Use Sourdough Starter?
The acidity in the sourdough starter adds to the tender crumb of this cake and helps it rise. It reacts with the baking soda to give it a fluffy yet still moist texture.
This cake can either be baked in one larger 22cm round cake tin, or two smaller 18cm cake tins. I like baking it in the two smaller ones, and sandwiching them together. It makes a compact but reasonably tall cake.
If baking in one tin, it can be sliced in half once baked and cooled to make a double layer cake.
The cake is topped with a creamy chocolate butter cream. Butter is first whipped until light, then icing sugar (confectioner’s sugar) and cocoa are added in, along with a little milk. Then whipped until it’s light, creamy and easily spread over the cake.
Spread 1/4 of the frosting on one cake round, so it reaches the edges. Add the second cake round on top. Top this round with another 1/4 of the frosting and spread it out. Use the remaining frosting to cover the edges of the cake and use a dough scraper to smooth it out.
The Chocolate Ganache
Afterwards, it is topped with a glossy and rich chocolate ganache. This part is optional, but it adds a real decadent touch to the chocolate cake.
The ganache is made by heating the cream first in a small saucepan until just simmering, taking it off the heat and adding in the chocolate chips. Let them melt, then stir it together until glossy.
Leave the ganache to cool and thicken a bit first before pouring on the cake so it can be spread in a thick layer.
Have you made this? Tag me and let me know! @home_grown_happinessnz
Sourdough Chocolate Cake
- 1 1/2 cups all purpose flour 225g
- 3/4 cup cocoa (70g)
- 1/2 tsp salt
- 1 tsp baking powder
- 1 tsp baking soda
- 2 eggs
- 1 tsp vanilla extract
- 3/4 cup vegetable oil 187ml
- 1/2 cup 'discard' sourdough starter 100g
- 2/3 cup granulated sugar 130g
- 2/3 cup soft brown sugar 130g
- 1 cup milk 250ml
- 1/2 cup hot strong coffee 125ml
- 200 g softened butter
- 2 1/2 – 3 cups icing sugar 320-375g
- 1/3 cup cocoa powder 30g
- 2-3 Tbsp milk or cream at room temperature
- 1/4 tsp salt (if using unsalted butter)
- 1/2 cup pouring cream 125ml
- 1 cup semi sweet chocolate chips 150g
- Preheat the oven to 180°C (356°F) and grease and line one 22 cm cake tin or two 18cm cake tins.
- In a bowl, mix together the flour, cocoa, salt, baking powder and baking soda. Set aside.
- In another bowl, whisk together the sourdough starter, eggs, vanilla, oil, milk and sugars.
- Pour the 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.
- Pour into the prepared cake tin and bake for 35-40 minutes until a skewer inserted into the cake comes out clean. If you are using two smaller cake tins, check them after 25-30 minutes.
- Beat the butter until light and creamy.
- Carefully add in the icing sugar and cocoa (powder will puff up so take care!).
- Once incorporated, beat on high for 5 minutes and add in 2-3 tablespoons of milk or cream as needed until it is light, creamy and spreadable.
- Heat the cream until just simmering. Take it off the heat and add the chocolate chips. Leave it to sit for 5 minutes, then stir until it is glossy and the chocolate has melted.
- Let it cool down until it has thickened a bit before pouring on the cake.