Lemon Olive Oil Sourdough Cake

A tender, citrus-bright layer cake with olive oil moisture and subtle sourdough depth.

Ingredients

Cake

• 3 cups (360 g) all-purpose flour

• 1 ¾ cups (350 g) granulated sugar

• 1 tsp salt

• 1 ½ tsp baking powder

• ¾ tsp baking soda

• ¾ cup (150 g) sourdough discard

• 1 ¼ cups (300 g) whole milk

• 1 ½ cups (315 g) olive oil

• 5 large eggs

• Juice of 1 ½ lemons (about 3–4 tbsp)

Buttercream

• 1 1/4 cups (300g) whole milk

• 1 1/2 cups (300g) granulated sugar

• 1/3 teaspoon salt

• 1/4 cup (120g) sourdough discard, room temperature

• 1 1/2 cups (3 sticks; 340g) unsalted butter, softened

• 1 1/2 teaspoon vanilla extract

• Optional: zest of 1 lemon or 2 Tablespoons lemon juice for extra citrus flavor

Instructions

Make the Cake

• Preheat oven to 350°F (175°C). Grease and line three 6-inch cake pans with parchment paper.

• Whisk together flour, sugar, salt, baking powder, and baking soda in a large bowl.

• In another bowl, whisk sourdough discard, milk, olive oil, eggs, and lemon juice.

• Add wet to dry and stir until just combined. Don’t overmix.

• Divide evenly into pans and bake 25–30 minutes, until a toothpick comes out clean.

• Cool 10 minutes in pans, then transfer to wire rack to cool completely.

Make the Buttercream

1. In a saucepan, heat milk, sugar, and salt until sugar dissolves. Cool to room temperature.

2. Whisk in sourdough discard until smooth.

3. Beat butter in a stand mixer until pale and fluffy (3–4 minutes).

4. Slowly pour in the milk/discard mixture while beating. Continue until smooth and creamy.

5. Mix in vanilla (and lemon zest/juice if using).

Assemble

1. Level cakes if needed.

2. Spread buttercream between layers, then frost the outside.

3. Chill 20 minutes before slicing.

Notes

• For a single 9-inch round cake: Use the following amounts:

  • 2 cups (240 g) flour

  • 1 ¼ cups (250 g) sugar

  • ¾ tsp salt

  • 1 tsp baking powder

  • ½ tsp baking soda

  • ½ cup (100 g) sourdough discard

  • ¾ cup (180 g) milk

  • 1 cup (210 g) olive oil

  • 3 large eggs

  • Juice of 1 lemon (2–3 tbsp)

  • Buttercream: 200 g milk, 200 g sugar, ¼ tsp salt, 80 g discard, 226 g butter, 1 tsp vanilla

• Pan Size Conversion Guide:

  • 2 × 8-inch rounds = full recipe

  • 1 × 9-inch square = full recipe

  • 1 × 9×13-inch rectangle = 1.5× recipe

  • Cupcakes (12 standard) = ½ recipe (18–22 min bake)