Cakespy: Chocolate Stout Cupcakes with Irish Whiskey Filling

1 cup stout (such as Guinness)

1 cup (2 sticks) unsalted butter

3/4 cup unsweetened cocoa powder

2 cups flour

2 cups sugar

1 1/2 teaspoons baking soda

3/4 teaspoon salt

2 large eggs

2/3 cup sour cream (full fat is best)

For the filling:

8 ounces bittersweet chocolate

1/3 cup heavy cream

1/3 cup Bailey's Irish Cream (the original recipe calls for 2/3 heavy cream and no Bailey's in the filling, but I found it increased the awesome quotient just a little bit)

2 tablespoons butter, room temperature

1 to 2 teaspoons Irish whiskey

For the frosting

Note: If you want lots of frosting on each cake, go ahead and double this recipe

3 to 4 cups confections' sugar

1 stick (1/2 cup) unsalted butter, at room temperature

3 to 4 tablespoons Bailey's Irish Cream (or more, to taste)