Adapted from NYT Cooking
FOR THE CAKE
Butter for the pan
1 cup Guinness stout
10 tablespoons (1 stick plus 2 tablespoons) unsalted butter
¾ cup unsweetened cocoa
2 cups superfine sugar
¾ cup sour cream
2 large eggs
1 tablespoon vanilla extract
2 cups all-purpose flour
2 ½ teaspoons baking soda
FOR THE ICING
8 ounces cream cheese, at room temperature
4 tablespoons butter, at room temperature
3 cups powdered sugar
3 – 4 tablespoons Baileys Irish Cream
For the cake: heat oven to 350 degrees. Butter a 9-inch springform pan and line with parchment paper. In a large saucepan, combine Guinness and butter. Place over medium-low heat until butter melts, then remove from heat. Add cocoa and superfine sugar, and whisk to blend.
In a small bowl, combine sour cream, eggs and vanilla; mix well. Add to the Guinness mixture. Add flour and baking soda and whisk again until smooth. Pour into a buttered pan, and bake until risen and firm, about 50 minutes. Place the pan on a wire rack and cool completely.For the frosting, add soft cream cheese, butter, powdered sugar and Bailey’s Irish Cream to a medium mixing bowl. Whip until smooth.
Remove cake from pan and place on a platter or cake stand. Ice top of cake only, so that it resembles a frothy pint of Guinness.