Decadent Sourdough Vanilla Cake with Discard

I never thought my sourdough starter discard would end up in a cake. Growing up, we always tossed the extra starter in the trash – that’s just what mom did. When my friend suggested using it in baking sweets, I looked at her like she had two heads.

Turns out, using sourdough discard in cake isn’t weird at all – it’s actually pretty smart. The natural tang adds something special to vanilla cake, and it means less waste from your starter. Plus, it’s as simple as using regular ingredients, just with a sourdough twist. For anyone who hates throwing away that extra starter, this recipe is for you.

What Kind of Sourdough Starter Should I Use?

For this cake recipe, you can use either active or discard sourdough starter – both will work great since we’re not relying on it for rise (that’s what the baking powder and soda are for). Your starter can be at any point in its feeding schedule, though a room temperature starter will blend more easily with the other ingredients. If you’re using starter straight from the fridge, let it sit out for about 30 minutes to take the chill off. The main thing is to make sure your starter has a consistency similar to pancake batter – if it’s too thick or thin, it might throw off the liquid ratio in your cake. Don’t worry too much about whether your starter is super sour or mild – the sugar and vanilla in this recipe will balance out any tanginess.

Options for Substitutions

This cake recipe has room for several ingredient swaps if you need them:

• Sourdough starter: This is a key ingredient that gives the cake its special texture and flavor. If you don’t have active starter, you can use discard that’s up to 1 week old from the fridge. Just make sure to bring it to room temperature first.
• Coconut oil: You can replace this with an equal amount of vegetable oil, canola oil, or just use all butter instead. Each option will work fine, though coconut oil adds a subtle sweetness.
• Milk/water: Feel free to use any type of milk – whole, 2%, almond, or soy milk all work well. Buttermilk is also a good option, but reduce the baking powder to 1 1/2 teaspoons if you use it.
• Thick cream: For the frosting, you can swap thick cream with whole milk, half-and-half, or even coconut cream. Start with less liquid and add more as needed to get the right consistency.
• All-purpose flour: Cake flour works great here too – use 2 3/4 cups cake flour for a softer texture. Just don’t use bread flour as it will make the cake tough.
• Icing sugar: Also called powdered or confectioner’s sugar – this is essential for the frosting texture and can’t be substituted with regular sugar.

Watch Out for These Mistakes While Baking

The temperature of your ingredients plays a crucial role in this sourdough cake – using cold sourdough starter, eggs, or butter straight from the fridge can lead to a lumpy batter and uneven texture, so make sure all ingredients are at room temperature before starting.

When incorporating the sourdough starter, avoid overmixing the batter as this can lead to a tough, dense cake – instead, fold it in gently just until combined, and remember that a few small lumps are perfectly fine.

Many bakers make the mistake of opening the oven door too frequently while the cake bakes, which causes uneven rising and potential sinking in the middle – resist the urge to peek and wait until at least 80% of the baking time has passed before checking for doneness.

For the best flavor development, don’t rush to frost the cake – allow it to cool completely (at least 2 hours) before adding any frosting, and if your room is warm, pop the layers in the fridge for 15 minutes before assembling to prevent the buttercream from melting.

What to Serve With Sourdough Vanilla Cake?

This sourdough vanilla cake pairs wonderfully with a hot cup of coffee or tea for the perfect afternoon treat. Since the cake has a unique tang from the sourdough starter, it goes really well with fresh berries or a dollop of whipped cream to balance out the flavors. For an extra special dessert, try serving it with a scoop of vanilla ice cream and a drizzle of caramel sauce, or keep things simple with a light dusting of powdered sugar on top. If you’re serving this at a party, consider putting out some fresh fruit compote on the side so guests can customize their slice.

Storage Instructions

Counter Storage: This sourdough vanilla cake stays fresh at room temperature for up to 2 days when stored in an airtight container. If you live somewhere humid, it’s better to pop it in the fridge instead of leaving it out on the counter.

Refrigerate: Keep your frosted cake in the fridge for up to 5 days. The butter-based frosting will firm up when cold, so I recommend letting slices sit at room temperature for about 20 minutes before serving to get that perfect creamy texture back.

Freeze: You can freeze unfrosted cake layers wrapped well in plastic wrap and foil for up to 3 months. For frosted cake, freeze individual slices on a baking sheet until firm, then wrap each piece well. When you’re ready to eat, thaw overnight in the fridge.

Make Ahead: Want to get ahead? Bake the cake layers up to 2 days before you need them. Just wrap them well and keep them at room temperature. You can also make the frosting a day ahead and store it in the fridge – just let it come to room temperature and give it a quick whip before frosting the cake.

Preparation Time	20-30 minutes
Cooking Time	30-45 minutes
Total Time	50-75 minutes
Level of Difficulty	Medium

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 4500-4800
• Protein: 50-60 g
• Fat: 250-270 g
• Carbohydrates: 540-580 g

Ingredients

• 2 1/2 cups all-purpose flour
• 2 cups granulated sugar
• 1 teaspoon salt
• 1 teaspoon baking soda
• 2 teaspoons baking powder
• 1/4 cup softened butter
• 1/4 cup coconut oil
• 1 1/2 tablespoons vanilla essence
• 1/2 cup sourdough starter
• 1 cup water or milk
• 3 large eggs
• 1 cup unsalted butter, softened
• 4 cups icing sugar
• 1/4 cup thick cream
• 1 tablespoon vanilla extract
• 1/2 teaspoon salt

Step 1: Prepare Baking Equipment

Preheat your oven to 350°F (175°C).

Grease a 9×13 inch baking dish or two 9-inch cake pans to prevent sticking.

Step 2: Combine Dry and Butter Ingredients

In a stand mixer bowl or a large mixing bowl, combine your dry ingredients.

Add softened butter to the flour mixture in this bowl and combine them until they form a crumbly texture.

Step 3: Mix Wet Ingredients

In a separate bowl, mix together your liquid ingredients: sourdough starter, milk, eggs, melted coconut oil, and vanilla extract.

Stir until they are well combined.

Step 4: Create the Cake Batter

Slowly incorporate the wet ingredients into the butter-flour mixture.

Start the mixer on a low setting to avoid splattering, and then gradually increase to medium speed.

Blend the ingredients until you achieve a smooth consistency without lumps.

Step 5: Bake the Cake

Pour the cake batter into the prepared baking dish or split evenly between the two cake pans.

Bake in the preheated oven for 30-35 minutes if using the 9×13 dish, or 35-45 minutes for the 9-inch cake pans.

The cake is done when it starts to turn golden around the edges and a cake tester inserted into the center comes out clean.

Allow the cake to cool completely before applying frosting.

Step 6: Prepare the Frosting

In a stand mixer with a whisk attachment or using a bowl and hand mixer, add softened butter and beat until smooth.

Gradually add powdered sugar, starting the mixer on low and increasing to medium speed.

Whisk until the frosting is fluffy, making sure to scrape the sides of the bowl as needed.

Finally, add whipping cream, salt, and vanilla.

Whisk for an additional 1-2 minutes to combine.

Step 7: Frost the Cake

Once the cake is completely cooled, evenly spread the frosting over the cake.

Use a spatula or knife to create a smooth surface or decorative patterns as desired.

Your cake is now ready to serve and enjoy!