- 1 cup Guinness stout
- 1 cup (2 sticks) unsalted butter, at room temperature
- ¾ cup Dutch-process cocoa powder
- 2 cups all-purpose flour
- 2 cups granulated sugar
- 1½ teaspoons baking soda
- ¾ teaspoons salt
- 2 eggs
- 2/3 cup sour cream
- Preheat oven to 350 degrees F.
- Line 24 cupcake cups with liners.
- Bring the Guinness and butter to a simmer in a heavy, medium saucepan over medium heat. Add the cocoa powder and whisk until the mixture is smooth. Cool slightly.
- Whisk the flour, sugar, baking soda and salt in a large bowl to combine.
- Using an electric mixer, beat the eggs and sour cream on medium speed until combined.
- Add the Guinness-chocolate mixture to the egg mixture and beat just to combine.
- Reduce the speed to low, add the flour mixture and beat briefly. Using a rubber spatula, fold the batter until completely combined.
- Divide the batter among the cupcake liners.
- Bake until a thin knife inserted into the center comes out clean, about 17 minutes.
- Cool the cupcakes on a rack.