Ingredients
Equipment
Method
- Preheat oven to 350°F (175°C). Grease and line the bottoms of three 8-inch round cake pans with parchment paper.
- In a medium saucepan over medium heat, combine Guinness and butter. Heat, stirring occasionally, until butter is melted. Remove from heat.
- Immediately whisk the cocoa powder into the warm Guinness-butter mixture until smooth. Let cool for 10-15 minutes.
- In a large bowl, whisk together sugar, sour cream, eggs, egg yolk, vegetable oil, and vanilla extract until smooth and well-combined.
- Gradually pour the cooled chocolate mixture into the sugar-egg mixture, whisking constantly until fully combined.
- Sift the flour, baking soda, and salt over the wet ingredients. Gently fold with a spatula until just combined and no dry streaks remain.
- Divide batter evenly among the prepared pans. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.
- Let cakes cool in pans for 10 minutes, then turn out onto a wire rack to cool completely.
- For the frosting, beat the softened butter with an electric mixer on medium-high speed for 2-3 minutes until pale and fluffy.
- Gradually add the sifted powdered sugar, one cup at a time, beating well after each addition.
- Add 6 tablespoons of Baileys, the heavy cream, and salt. Beat on medium-high speed for 3-4 minutes until light, smooth, and holding stiff peaks. Add more Baileys to taste.
- Place one cooled cake layer on a serving plate. Spread with about 1 cup of frosting. Repeat with remaining layers.
- Apply a thin crumb coat of frosting over the entire cake. Chill for 15 minutes, then frost with the remaining frosting.
Notes
Ensure all refrigerated ingredients (eggs, sour cream, butter for frosting) are at room temperature to prevent a lumpy batter or curdled frosting. Do not overmix the batter after adding flour to keep the cake tender. The cake layers must be completely cool before frosting. Store covered at room temperature for up to 2 days or refrigerated for up to 5 days. For a non-alcoholic version, replace Guinness with strong coffee and the Baileys with 2 tsp vanilla extract plus milk/cream. Full-fat Greek yogurt can substitute for sour cream.