-
1
Preheat the oven to 325 degrees F. Line a cupcake or muffin pan with 24 regular-size cupcake liners.
-
2
Place the stout and butter in a medium-size saucepan and whisk together on medium heat until the butter is melted.
-
3
Remove from the heat.
-
4
Sift the cocoa powder into a medium-size bowl and add the sugar.
-
5
Slowly whisk into the stout mixture.
-
6
In a small bowl, combine the sour cream, eggs, and vanilla and lightly whisk until smooth.
-
7
Add this mixture to the saucepan and whisk thoroughly (it may appear lumpy).
-
8
Sift the flour and baking soda together in another small bowl and then add it to the saucepan, mixing a final time until the color is even.
-
9
Fill the cupcake liners three-quarters full with batter and bake until the cakes spring back after touching, about 27 minutes.
-
10
Cool the cupcakes in their pan for 5 minutes before transferring to a cooling rack.
-
11
To assemble: Pipe the frosting onto cooled cupcakes using a large plain tip.
-
12
Dust with cocoa powder if preferred.
-
13
Cream the butter in the bowl of an electric stand mixer until pale.
-
14
Turn the mixer to low speed and add the Irish liqueur in a steady stream.
-
15
Slowly add the confectioners' sugar and continue beating until a creamy consistency is achieved.
