I forgot to put the Bailey's in the picture. You'll need a little bit for the icing. (Recipe is in Italics, my notes are in regular font)
For the Guinness Chocolate Cupcakes:
1 cup stout (such as Guinness)
1 cup (2 sticks) unsalted butter
3/4 cup unsweetened cocoa powder
2 cups all purpose flour
2 cups sugar
1 1/2 teaspoons baking soda
3/4 teaspoon salt
2 large eggs
2/3 cup sour cream
Preheat oven to 350°F. Line 24 cupcake cups with liners. Bring 1 cup stout and 1 cup butter to simmer in heavy large saucepan over medium heat.
8 ounces bittersweet chocolate
2/3 cup heavy cream
2 tablespoons butter, room temperature
1 to 2 teaspoons Irish whiskey (optional)
Heat the cream until simmering and pour it over the chocolate. Let it sit for one minute and then stir until smooth. Add the butter and whiskey (if you’re using it) and stir until combined. The bf accidentally bought 'whipping cream' not 'heavy cream' but seemed fine. After the cream was heated, we just dumped in the chocolate chips, which happened to be semi-sweet not bittersweet since the store was out. I also only put 1/2 teaspoon of whiskey because I didn't want it to be overpowering.
The recipe suggested using an apple corer or a 1 inch cookie cutter. We had neither of those, so we used a teaspoon to scoop some of the cake out. Let the filling cool a bit before piping it. Put the ganache into a ziplock bag, cut of a corner, and piped it into the middle.
3 to 4 cups confections sugar
1 stick (1/2 cup or 4 ounces) unsalted butter, at room temperature
3 to 4 tablespoons Baileys (or milk, or heavy cream, or a combination thereof)
Whip the butter in the bowl of an electric mixer, or with a hand mixer, for several minutes. You want to get it very light and fluffy. Slowly add the powdered sugar, a few tablespoons at a time.