Ingredients:
- 375g cake flour
- 400g granulated sugar
- 12g baking powder
- 3g salt
- 225g unsalted butter, room temperature, cubed
- 180ml whole milk, room temperature
- 60ml buttermilk, room temperature
- 60g full-fat sour cream
- 3 large egg yolks
- 2 large eggs
- 15ml vanilla bean paste or extract
- 340g unsalted butter, softened
- 500g powdered sugar, sifted
- 95g Dutch-process cocoa powder
- 45ml heavy cream
- 2g espresso powder
Instructions:
- Preheat your oven to 350°F (175°C). Grease and line two 8-inch round cake pans with parchment paper.
- Sift the cake flour, granulated sugar, baking powder, and salt into the bowl of a stand mixer.
- With the paddle attachment on low speed, add the 225g of cubed butter one piece at a time. Continue mixing until the texture resembles fine, damp sand with no large butter chunks remaining.
- In a separate medium bowl, whisk together the milk, buttermilk, sour cream, egg yolks, whole eggs, and vanilla.
- Slowly pour the liquid ingredients into the dry mixture while the mixer is on low. Increase to medium speed and beat for 60-90 seconds to develop the cake's structure.
- Divide the batter evenly between the prepared pans. Bake for 28-32 minutes, or until a toothpick inserted into the center comes out clean.
- Cool cakes in the pans for 10 minutes before inverting onto a wire rack to cool completely.
- Prepare the buttercream: Beat the 340g softened butter until creamy. Gradually add powdered sugar and cocoa powder on low speed. Add heavy cream and espresso powder, then whip on high for 3 minutes until silky.
- Frost the cooled cake layers and serve.