Adapted from Nigella Lawson
For the cake:
Butter for pan
1 cup Guinness stout
10 tablespoons (1 stick plus 2 tablespoons) butter
1/4 cup plus 2 tablespoons unsweetened cocoa
2 cups sugar
1/4 cup plus 2 tablespoons sour cream
1 tablespoon vanilla extract
2 cups all-purpose flour
2 1/2 teaspoons baking soda
1 1/4 cups powdered sugar
8 ounces cream cheese, at room temperature
1/2 cup heavy cream
1 teaspoon vanilla
Preheat oven to 350º. Butter a 9-inch springform pan and line with parchment paper. In a pan, combine Guinness and butter. Place over medium heat until butter melts, then remove from heat. Add cocoa and sugar, and whisk to blend.
In a large bowl, combine sour cream, eggs and vanilla; mix well. Add Guinness mixture to bowl and whisk. Add flour and baking soda, and whisk again until smooth. Pour into prepared pan, and bake until risen and firm, 45 minutes to one hour. Place pan on a wire rack and cool completely in pan.
Sift powdered sugar into medium bowl to break up lumps. Add cream cheese and blend until smooth. Add heavy cream and vanilla, and mix until smooth.
Remove cake from pan and place on serving dish. Ice top of cake only, so that it resembles a frothy pint of Guinness.