-
1
Preheat oven to 350 degrees.
-
2
Whisk together flour and baking soda.
-
3
Pour Guinness into a small saucepan and add butter. Slowly heat on the stove top until butter is melted.
-
4
Once butter is melted, whisk in cocoa powder and sugar until combined.
-
5
Combine eggs and yogurt in a large bowl and beat with a mixer until combined.
-
6
Slowly add Guinness mixture to eggs and yogurt and beat with the mixer.
-
7
Add in flour mixture and beat until well combined.
-
8
Fill a cake pan or baking cups and bake until a toothpick inserted into the middle comes out clean. My oven takes approx 15 minutes for cupcakes, but yours may differ.
-
9
For the frosting:
-
10
Place sugar and egg whites in the heatproof bowl of an electric mixer. Set bowl over a pan of gently simmering water, and whisk until sugar has dissolved and egg whites are hot to the touch, about 3 minutes. Test by rubbing the mixture between your fingers; it should feel completely smooth.
-
11
Transfer the bowl to the mixer stand (or hot pad if using a hand mixer). Using the whisk attachment, beat on high speed until mixture has cooled completely and formed stiff and glossy peaks, about 10 minutes.
-
12
Add the butter, one piece at a time, and beat until incorporated after each addition. Don't worry if the buttercream appears curdled after all the butter has been added; it will become smooth again with continued beating. Add Bailey's, and beat just until combined.
-
13
Make sure the cupcakes are fully cooled before frosting, as buttercream melts extremely easily!
